<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:5286d007-5e02-43f2-90d0-885a55f4a3fa,g:e8391680-0c31-45bb-baca-4cab2eb1ba91-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.allete.com/role/DocumentandEntityInformationDocument" xlink:type="simple" xlink:href="ale-20210930.xsd#DocumentandEntityInformationDocument"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/DocumentandEntityInformationDocument" xlink:type="extended" id="icca034710d9f4f348e1709611d33d2f4_DocumentandEntityInformationDocument">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_119a82f8-ea6f-4eaf-9844-2292b11eef7f" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentType_119a82f8-ea6f-4eaf-9844-2292b11eef7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_ff746d21-5097-48bf-8c1b-05631a1aad20" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentQuarterlyReport_ff746d21-5097-48bf-8c1b-05631a1aad20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_7ddaf266-6990-4c68-83d6-fb04bea0bdfd" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentPeriodEndDate_7ddaf266-6990-4c68-83d6-fb04bea0bdfd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_3ad24ba3-3721-4738-a4b7-0d1985ced8be" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentTransitionReport_3ad24ba3-3721-4738-a4b7-0d1985ced8be" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_70e02269-ea5d-4bea-80a8-2249820e3eb3" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityFileNumber_70e02269-ea5d-4bea-80a8-2249820e3eb3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_e85892e5-3076-4561-bafb-78ffad5a135c" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityRegistrantName_e85892e5-3076-4561-bafb-78ffad5a135c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_67c9aff3-477b-4f26-93b3-d7d388662254" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityIncorporationStateCountryCode_67c9aff3-477b-4f26-93b3-d7d388662254" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_8b903b6e-800e-40b6-923b-5d39d30746f7" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityTaxIdentificationNumber_8b903b6e-800e-40b6-923b-5d39d30746f7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_04c6556d-750e-4610-a25d-e7879acd8387" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityAddressAddressLine1_04c6556d-750e-4610-a25d-e7879acd8387" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_6990a990-147b-4b8c-a931-d204d9263eb8" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityAddressCityOrTown_6990a990-147b-4b8c-a931-d204d9263eb8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_b9122a0e-a6ed-43f4-af47-e33d150569b5" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityAddressStateOrProvince_b9122a0e-a6ed-43f4-af47-e33d150569b5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_a7ab1ce5-57f7-4838-b610-086388f7002c" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityAddressPostalZipCode_a7ab1ce5-57f7-4838-b610-086388f7002c" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_7dafaba3-95c8-44a0-b088-b773a27ad636" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_CityAreaCode_7dafaba3-95c8-44a0-b088-b773a27ad636" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_a14a6623-d125-4495-aee1-6ad5a0f54bb0" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_LocalPhoneNumber_a14a6623-d125-4495-aee1-6ad5a0f54bb0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_5df6cd31-1806-4a06-bb15-54c26bfadcd6" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_Security12bTitle_5df6cd31-1806-4a06-bb15-54c26bfadcd6" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_54650136-5156-4b50-9992-2c6460f7972f" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_TradingSymbol_54650136-5156-4b50-9992-2c6460f7972f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_17074feb-5972-4e99-9771-7753096dd98b" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_SecurityExchangeName_17074feb-5972-4e99-9771-7753096dd98b" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_a46cea16-45ab-4952-8148-2228838e81be" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityCurrentReportingStatus_a46cea16-45ab-4952-8148-2228838e81be" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_1c5a4679-036f-48b7-b77b-563444eda055" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityInteractiveDataCurrent_1c5a4679-036f-48b7-b77b-563444eda055" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_c3a8173b-f17e-4e2c-bc79-491a0f520e05" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityFilerCategory_c3a8173b-f17e-4e2c-bc79-491a0f520e05" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_dbc784bd-6b0f-448c-b7bb-3f19466593c8" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityShellCompany_dbc784bd-6b0f-448c-b7bb-3f19466593c8" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_ff4ad66f-eb1e-4e20-9cbb-a2438d0574f6" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_ff4ad66f-eb1e-4e20-9cbb-a2438d0574f6" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_9b1f8b37-0f8d-4463-a13a-862470487464" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityCentralIndexKey_9b1f8b37-0f8d-4463-a13a-862470487464" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_cd96f85a-702f-4cec-a42f-b03e9135edd2" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_CurrentFiscalYearEndDate_cd96f85a-702f-4cec-a42f-b03e9135edd2" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_8a0ad7f5-557b-4ba6-89f1-1c2d98831638" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentFiscalYearFocus_8a0ad7f5-557b-4ba6-89f1-1c2d98831638" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_ad0f5eef-ad17-404f-ba9a-d55e0193ae99" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentFiscalPeriodFocus_ad0f5eef-ad17-404f-ba9a-d55e0193ae99" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_c87896e7-f842-4f33-948f-9ef060564822" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_AmendmentFlag_c87896e7-f842-4f33-948f-9ef060564822" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_51a84e11-5fe2-4ef2-81cd-bdf58556b0a9" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntitySmallBusiness_51a84e11-5fe2-4ef2-81cd-bdf58556b0a9" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_21734c0d-1864-45cf-9f98-79e9cf2cfd0f" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_EntityEmergingGrowthCompany_21734c0d-1864-45cf-9f98-79e9cf2cfd0f" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_598a848c-2fb7-483e-9228-024c858455d1" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_20615c8e-f576-4245-a59a-b71418cbbc86" xlink:to="loc_dei_DocumentInformationTable_598a848c-2fb7-483e-9228-024c858455d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationDocumentAxis_05d02e8b-0b82-47b9-a38f-76eb97fcbdd2" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentInformationDocumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_598a848c-2fb7-483e-9228-024c858455d1" xlink:to="loc_dei_DocumentInformationDocumentAxis_05d02e8b-0b82-47b9-a38f-76eb97fcbdd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_05d02e8b-0b82-47b9-a38f-76eb97fcbdd2_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_DocumentInformationDocumentAxis_05d02e8b-0b82-47b9-a38f-76eb97fcbdd2" xlink:to="loc_dei_DocumentDomain_05d02e8b-0b82-47b9-a38f-76eb97fcbdd2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_0294b226-46a4-49c9-b5c7-698afd6be1c7" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_DocumentInformationDocumentAxis_05d02e8b-0b82-47b9-a38f-76eb97fcbdd2" xlink:to="loc_dei_DocumentDomain_0294b226-46a4-49c9-b5c7-698afd6be1c7" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/ConsolidatedStatementofEquity" xlink:type="simple" xlink:href="ale-20210930.xsd#ConsolidatedStatementofEquity"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/ConsolidatedStatementofEquity" xlink:type="extended" id="i21150ee099a04cc9baa7611ce4066e40_ConsolidatedStatementofEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_580024df-703f-4f67-bdbf-66d1714a1be4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_580024df-703f-4f67-bdbf-66d1714a1be4" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9909b9fb-517f-4171-b96f-dcf68eb88a11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9909b9fb-517f-4171-b96f-dcf68eb88a11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_23748ba5-5cd2-4f1d-98f5-7104719b554c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_23748ba5-5cd2-4f1d-98f5-7104719b554c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_ad4bbdad-6638-4bf1-a2ac-a6893dea46f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_ad4bbdad-6638-4bf1-a2ac-a6893dea46f7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a5f79f04-9a95-46da-b2bd-496404a30d94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_NetIncomeLoss_a5f79f04-9a95-46da-b2bd-496404a30d94" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_fcb14608-d223-4035-8e1a-df775ac6efa7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_fcb14608-d223-4035-8e1a-df775ac6efa7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_9b9f45a5-8b6b-4ccc-8c13-f9cc3c444d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_9b9f45a5-8b6b-4ccc-8c13-f9cc3c444d5c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_83301488-91ed-4159-a5b6-eae6b493d084" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_83301488-91ed-4159-a5b6-eae6b493d084" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_608647f5-0a67-46d5-8978-ad3323d1e183" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d1293934-6b64-4d42-b811-83c44f7981cf" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_608647f5-0a67-46d5-8978-ad3323d1e183" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_74759700-396e-4064-b4b6-1c7b5155b2e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_d40aa249-67d6-46bf-bbd7-362c8f6db4c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_580024df-703f-4f67-bdbf-66d1714a1be4" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_d40aa249-67d6-46bf-bbd7-362c8f6db4c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_3c559eba-3306-4f2b-ae95-6244ade372b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_580024df-703f-4f67-bdbf-66d1714a1be4" xlink:to="loc_us-gaap_StatementTable_3c559eba-3306-4f2b-ae95-6244ade372b2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_3d6577a0-b0c3-43b3-a3f8-4b775a964b2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3c559eba-3306-4f2b-ae95-6244ade372b2" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_3d6577a0-b0c3-43b3-a3f8-4b775a964b2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3d6577a0-b0c3-43b3-a3f8-4b775a964b2e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_3d6577a0-b0c3-43b3-a3f8-4b775a964b2e" xlink:to="loc_us-gaap_EquityComponentDomain_3d6577a0-b0c3-43b3-a3f8-4b775a964b2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8f910006-d2c8-4f7f-a463-b7914b299cd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_3d6577a0-b0c3-43b3-a3f8-4b775a964b2e" xlink:to="loc_us-gaap_EquityComponentDomain_8f910006-d2c8-4f7f-a463-b7914b299cd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_3c4163e8-2c18-4657-87f1-58b96699d3d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8f910006-d2c8-4f7f-a463-b7914b299cd4" xlink:to="loc_us-gaap_CommonStockMember_3c4163e8-2c18-4657-87f1-58b96699d3d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_1a84d376-15c4-4344-b128-1eed0aa43625" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8f910006-d2c8-4f7f-a463-b7914b299cd4" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_1a84d376-15c4-4344-b128-1eed0aa43625" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_953d61b5-7887-4acf-8df4-af807753b202" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8f910006-d2c8-4f7f-a463-b7914b299cd4" xlink:to="loc_us-gaap_RetainedEarningsMember_953d61b5-7887-4acf-8df4-af807753b202" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_e1c05450-21ec-4859-aeb3-bb39f65596ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8f910006-d2c8-4f7f-a463-b7914b299cd4" xlink:to="loc_us-gaap_NoncontrollingInterestMember_e1c05450-21ec-4859-aeb3-bb39f65596ee" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#OperationsandSignificantAccountingPoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesDetails" xlink:type="extended" id="i15f770df3e414e8ebc53e438c3222505_OperationsandSignificantAccountingPoliciesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_408f026a-c90e-4b6c-a219-f8a727200fa6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivables_f3d23ab6-0ab0-40f5-81b1-65169942745d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_408f026a-c90e-4b6c-a219-f8a727200fa6" xlink:to="loc_us-gaap_OtherReceivables_f3d23ab6-0ab0-40f5-81b1-65169942745d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_af58b9ac-563b-491a-a724-33362b526a12" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_408f026a-c90e-4b6c-a219-f8a727200fa6" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_af58b9ac-563b-491a-a724-33362b526a12" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_9554d0f8-88bc-468e-94ee-5851b13c3416" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_af58b9ac-563b-491a-a724-33362b526a12" xlink:to="loc_dei_LegalEntityAxis_9554d0f8-88bc-468e-94ee-5851b13c3416" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_9554d0f8-88bc-468e-94ee-5851b13c3416_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_9554d0f8-88bc-468e-94ee-5851b13c3416" xlink:to="loc_dei_EntityDomain_9554d0f8-88bc-468e-94ee-5851b13c3416_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_403ac9ca-058d-4d96-8735-2d599466527e" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_9554d0f8-88bc-468e-94ee-5851b13c3416" xlink:to="loc_dei_EntityDomain_403ac9ca-058d-4d96-8735-2d599466527e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_BNIEnergyMember_20d222aa-3a46-404e-bfb1-51712325b7bd" xlink:href="ale-20210930.xsd#ale_BNIEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_403ac9ca-058d-4d96-8735-2d599466527e" xlink:to="loc_ale_BNIEnergyMember_20d222aa-3a46-404e-bfb1-51712325b7bd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesOtherIncomeDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#OperationsandSignificantAccountingPoliciesOtherIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesOtherIncomeDetails" xlink:type="extended" id="i44b084cd139d4ac9b62e9c718a1e5d8e_OperationsandSignificantAccountingPoliciesOtherIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_ale_OtherIncomeExpenseOtherLineItems_0d47e8dd-9ada-4dc6-94ac-c544052ecf37" xlink:href="ale-20210930.xsd#ale_OtherIncomeExpenseOtherLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_8f90afc2-cedc-44de-b4a5-ba908eed9314" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_OtherIncomeExpenseOtherLineItems_0d47e8dd-9ada-4dc6-94ac-c544052ecf37" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_8f90afc2-cedc-44de-b4a5-ba908eed9314" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_OtherIncomeExpenseOtherTable_a17aed1d-4c4d-4d29-95d2-4d70110d3155" xlink:href="ale-20210930.xsd#ale_OtherIncomeExpenseOtherTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ale_OtherIncomeExpenseOtherLineItems_0d47e8dd-9ada-4dc6-94ac-c544052ecf37" xlink:to="loc_ale_OtherIncomeExpenseOtherTable_a17aed1d-4c4d-4d29-95d2-4d70110d3155" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ComponentofOtherIncomeExpenseOtherAxis_d1624405-363c-4ed1-9719-2dc465db6ea9" xlink:href="ale-20210930.xsd#ale_ComponentofOtherIncomeExpenseOtherAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_OtherIncomeExpenseOtherTable_a17aed1d-4c4d-4d29-95d2-4d70110d3155" xlink:to="loc_ale_ComponentofOtherIncomeExpenseOtherAxis_d1624405-363c-4ed1-9719-2dc465db6ea9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d1624405-363c-4ed1-9719-2dc465db6ea9_default" xlink:href="ale-20210930.xsd#ale_ComponentofOtherIncomeExpenseOtherDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_ComponentofOtherIncomeExpenseOtherAxis_d1624405-363c-4ed1-9719-2dc465db6ea9" xlink:to="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d1624405-363c-4ed1-9719-2dc465db6ea9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d98b6fc1-b255-4ad4-a07c-babdaa495528" xlink:href="ale-20210930.xsd#ale_ComponentofOtherIncomeExpenseOtherDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_ComponentofOtherIncomeExpenseOtherAxis_d1624405-363c-4ed1-9719-2dc465db6ea9" xlink:to="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d98b6fc1-b255-4ad4-a07c-babdaa495528" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_PensionandOtherPostretirementBenefitPlansNonServiceCreditMember_29f63ae5-82f3-4457-af7b-f30b54df4f8a" xlink:href="ale-20210930.xsd#ale_PensionandOtherPostretirementBenefitPlansNonServiceCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d98b6fc1-b255-4ad4-a07c-babdaa495528" xlink:to="loc_ale_PensionandOtherPostretirementBenefitPlansNonServiceCreditMember_29f63ae5-82f3-4457-af7b-f30b54df4f8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_InterestandInvestmentEarningsMember_eaa2e659-00ff-4359-b970-936614b54794" xlink:href="ale-20210930.xsd#ale_InterestandInvestmentEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d98b6fc1-b255-4ad4-a07c-babdaa495528" xlink:to="loc_ale_InterestandInvestmentEarningsMember_eaa2e659-00ff-4359-b970-936614b54794" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AFUDCEquityMember_9f9f7405-eaa8-4fe7-b10d-c00387f599b7" xlink:href="ale-20210930.xsd#ale_AFUDCEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d98b6fc1-b255-4ad4-a07c-babdaa495528" xlink:to="loc_ale_AFUDCEquityMember_9f9f7405-eaa8-4fe7-b10d-c00387f599b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_OtherIncomeExpenseOtherMember_17ccc23a-b3c0-4bdb-b012-c7a31dcb2517" xlink:href="ale-20210930.xsd#ale_OtherIncomeExpenseOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ComponentofOtherIncomeExpenseOtherDomain_d98b6fc1-b255-4ad4-a07c-babdaa495528" xlink:to="loc_ale_OtherIncomeExpenseOtherMember_17ccc23a-b3c0-4bdb-b012-c7a31dcb2517" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesNonControllingInterestDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#OperationsandSignificantAccountingPoliciesNonControllingInterestDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesNonControllingInterestDetails" xlink:type="extended" id="ic8cd4701b2c24370a9b59623cddf9a28_OperationsandSignificantAccountingPoliciesNonControllingInterestDetails">
    <link:loc xlink:type="locator" xlink:label="loc_ale_NonControllingInterestDetailsLineItems_0f2a5845-03ec-4319-b15d-235e3a3b736c" xlink:href="ale-20210930.xsd#ale_NonControllingInterestDetailsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingCapacitySubjecttoTaxEquityFinancing_545680b7-45b3-4cbe-810b-3172e32778e1" xlink:href="ale-20210930.xsd#ale_GeneratingCapacitySubjecttoTaxEquityFinancing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_NonControllingInterestDetailsLineItems_0f2a5845-03ec-4319-b15d-235e3a3b736c" xlink:to="loc_ale_GeneratingCapacitySubjecttoTaxEquityFinancing_545680b7-45b3-4cbe-810b-3172e32778e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_NonControllingInterestDetailsTable_4cc347b3-8776-46ec-bbe0-6198a000c994" xlink:href="ale-20210930.xsd#ale_NonControllingInterestDetailsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ale_NonControllingInterestDetailsLineItems_0f2a5845-03ec-4319-b15d-235e3a3b736c" xlink:to="loc_ale_NonControllingInterestDetailsTable_4cc347b3-8776-46ec-bbe0-6198a000c994" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityAxisAxis_c7ee356e-ef3b-4854-91e4-84552b5023ac" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityAxisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_NonControllingInterestDetailsTable_4cc347b3-8776-46ec-bbe0-6198a000c994" xlink:to="loc_ale_GeneratingFacilityAxisAxis_c7ee356e-ef3b-4854-91e4-84552b5023ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_c7ee356e-ef3b-4854-91e4-84552b5023ac_default" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GeneratingFacilityAxisAxis_c7ee356e-ef3b-4854-91e4-84552b5023ac" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_c7ee356e-ef3b-4854-91e4-84552b5023ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_d9339ec9-2d42-4e56-8a8a-4d5733c32437" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GeneratingFacilityAxisAxis_c7ee356e-ef3b-4854-91e4-84552b5023ac" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_d9339ec9-2d42-4e56-8a8a-4d5733c32437" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GlenUllinEnergyCenterMember_08d201dd-e6cf-4d81-ae5c-ce0de227a2ad" xlink:href="ale-20210930.xsd#ale_GlenUllinEnergyCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_d9339ec9-2d42-4e56-8a8a-4d5733c32437" xlink:to="loc_ale_GlenUllinEnergyCenterMember_08d201dd-e6cf-4d81-ae5c-ce0de227a2ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SouthPeakMember_978b0884-d6de-4a85-a0b1-fc06230f3955" xlink:href="ale-20210930.xsd#ale_SouthPeakMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_d9339ec9-2d42-4e56-8a8a-4d5733c32437" xlink:to="loc_ale_SouthPeakMember_978b0884-d6de-4a85-a0b1-fc06230f3955" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DiamondSpringMember_66b292a9-f4d3-4e9f-8624-c9810b16d101" xlink:href="ale-20210930.xsd#ale_DiamondSpringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_d9339ec9-2d42-4e56-8a8a-4d5733c32437" xlink:to="loc_ale_DiamondSpringMember_66b292a9-f4d3-4e9f-8624-c9810b16d101" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_Nobles2Member_b826616a-27ce-4585-af4b-4a1e7cd7a932" xlink:href="ale-20210930.xsd#ale_Nobles2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_d9339ec9-2d42-4e56-8a8a-4d5733c32437" xlink:to="loc_ale_Nobles2Member_b826616a-27ce-4585-af4b-4a1e7cd7a932" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesSubsequentEventsDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#OperationsandSignificantAccountingPoliciesSubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/OperationsandSignificantAccountingPoliciesSubsequentEventsDetails" xlink:type="extended" id="id5d04964a03c4703963a8f6c7ea7ca99_OperationsandSignificantAccountingPoliciesSubsequentEventsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ApproximateSalesPrice_28624472-c4bd-4a05-9194-67107db0ca61" xlink:href="ale-20210930.xsd#ale_ApproximateSalesPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_ale_ApproximateSalesPrice_28624472-c4bd-4a05-9194-67107db0ca61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased_ec1a60cd-830e-40d9-ab43-0a364120b6db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased_ec1a60cd-830e-40d9-ab43-0a364120b6db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GainOnSaleAfterTax_783fa89c-7d61-4caa-8415-93af71d7743f" xlink:href="ale-20210930.xsd#ale_GainOnSaleAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_ale_GainOnSaleAfterTax_783fa89c-7d61-4caa-8415-93af71d7743f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingCapacityJointlyOwnedMW_daa388db-7411-46af-9163-a18076a9ec95" xlink:href="ale-20210930.xsd#ale_GeneratingCapacityJointlyOwnedMW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_ale_GeneratingCapacityJointlyOwnedMW_daa388db-7411-46af-9163-a18076a9ec95" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DevelopmentCostsSold_3a6b7b55-3d58-4a8e-9b1b-8dc34e67a410" xlink:href="ale-20210930.xsd#ale_DevelopmentCostsSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_ale_DevelopmentCostsSold_3a6b7b55-3d58-4a8e-9b1b-8dc34e67a410" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_EstimatedCapitalExpendituresIncludingPastExpenditures_fd540942-46c8-4484-a03c-280e35f5ed6d" xlink:href="ale-20210930.xsd#ale_EstimatedCapitalExpendituresIncludingPastExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_ale_EstimatedCapitalExpendituresIncludingPastExpenditures_fd540942-46c8-4484-a03c-280e35f5ed6d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CapitalCostSpentToDate_b0fc1720-eab9-4c72-8edd-d8f21c29232a" xlink:href="ale-20210930.xsd#ale_CapitalCostSpentToDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_ale_CapitalCostSpentToDate_b0fc1720-eab9-4c72-8edd-d8f21c29232a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_fe01facd-8028-408d-9ffd-2fe4cbffc324" xlink:to="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeAxis_4a6bf092-3bfa-4e2e-b21a-54e27f7d6daf" xlink:href="ale-20210930.xsd#ale_GenerationTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:to="loc_ale_GenerationTypeAxis_4a6bf092-3bfa-4e2e-b21a-54e27f7d6daf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_4a6bf092-3bfa-4e2e-b21a-54e27f7d6daf_default" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GenerationTypeAxis_4a6bf092-3bfa-4e2e-b21a-54e27f7d6daf" xlink:to="loc_ale_GenerationTypeDomain_4a6bf092-3bfa-4e2e-b21a-54e27f7d6daf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_c830dae9-69a1-4a66-a7db-57225e186e3c" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GenerationTypeAxis_4a6bf092-3bfa-4e2e-b21a-54e27f7d6daf" xlink:to="loc_ale_GenerationTypeDomain_c830dae9-69a1-4a66-a7db-57225e186e3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NaturalGasProcessingPlantMember_cda0324b-4fb7-4791-84d5-5df86e38d259" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NaturalGasProcessingPlantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GenerationTypeDomain_c830dae9-69a1-4a66-a7db-57225e186e3c" xlink:to="loc_us-gaap_NaturalGasProcessingPlantMember_cda0324b-4fb7-4791-84d5-5df86e38d259" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_23e73dea-3385-46d5-af4a-b2c4a6f827be" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:to="loc_dei_LegalEntityAxis_23e73dea-3385-46d5-af4a-b2c4a6f827be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_23e73dea-3385-46d5-af4a-b2c4a6f827be_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_23e73dea-3385-46d5-af4a-b2c4a6f827be" xlink:to="loc_dei_EntityDomain_23e73dea-3385-46d5-af4a-b2c4a6f827be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_c8fc287b-7f94-496d-a82d-8bc8318e8392" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_23e73dea-3385-46d5-af4a-b2c4a6f827be" xlink:to="loc_dei_EntityDomain_c8fc287b-7f94-496d-a82d-8bc8318e8392" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SouthShoreEnergyMember_e8e427d9-1577-4ef0-b17d-af2a7de5842e" xlink:href="ale-20210930.xsd#ale_SouthShoreEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_c8fc287b-7f94-496d-a82d-8bc8318e8392" xlink:to="loc_ale_SouthShoreEnergyMember_e8e427d9-1577-4ef0-b17d-af2a7de5842e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_48d6442a-1b07-44b3-bfe5-722c5b459ded" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_48d6442a-1b07-44b3-bfe5-722c5b459ded" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_48d6442a-1b07-44b3-bfe5-722c5b459ded_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_48d6442a-1b07-44b3-bfe5-722c5b459ded" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_48d6442a-1b07-44b3-bfe5-722c5b459ded_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_f7da5f96-93a0-4159-9368-617903511951" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_48d6442a-1b07-44b3-bfe5-722c5b459ded" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_f7da5f96-93a0-4159-9368-617903511951" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_151056c2-185d-4858-a5b8-34c73f22c22a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_f7da5f96-93a0-4159-9368-617903511951" xlink:to="loc_us-gaap_SubsequentEventMember_151056c2-185d-4858-a5b8-34c73f22c22a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_fb50205c-615c-4251-9333-4e95b3ce130b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:to="loc_srt_CounterpartyNameAxis_fb50205c-615c-4251-9333-4e95b3ce130b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fb50205c-615c-4251-9333-4e95b3ce130b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_fb50205c-615c-4251-9333-4e95b3ce130b" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fb50205c-615c-4251-9333-4e95b3ce130b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_90aa8d8f-c659-4d64-9a5d-5d6e8d294387" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_fb50205c-615c-4251-9333-4e95b3ce130b" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_90aa8d8f-c659-4d64-9a5d-5d6e8d294387" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DairylandPowerCooperativeMember_0d65bc26-544c-4fe9-a80e-d25ea6f8a4d2" xlink:href="ale-20210930.xsd#ale_DairylandPowerCooperativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_90aa8d8f-c659-4d64-9a5d-5d6e8d294387" xlink:to="loc_ale_DairylandPowerCooperativeMember_0d65bc26-544c-4fe9-a80e-d25ea6f8a4d2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_BasinElectricPowerCooperativeMember_5c490b10-1c0b-4c38-a3a0-2539d5c5889c" xlink:href="ale-20210930.xsd#ale_BasinElectricPowerCooperativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_90aa8d8f-c659-4d64-9a5d-5d6e8d294387" xlink:to="loc_ale_BasinElectricPowerCooperativeMember_5c490b10-1c0b-4c38-a3a0-2539d5c5889c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityAxisAxis_a16ca90e-011f-4c4e-83aa-cbcc44563cae" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityAxisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_3073ac68-2aeb-421d-8b81-a841331231b7" xlink:to="loc_ale_GeneratingFacilityAxisAxis_a16ca90e-011f-4c4e-83aa-cbcc44563cae" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_a16ca90e-011f-4c4e-83aa-cbcc44563cae_default" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GeneratingFacilityAxisAxis_a16ca90e-011f-4c4e-83aa-cbcc44563cae" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_a16ca90e-011f-4c4e-83aa-cbcc44563cae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_009da211-d407-4aef-9f72-a75a135a22d7" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GeneratingFacilityAxisAxis_a16ca90e-011f-4c4e-83aa-cbcc44563cae" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_009da211-d407-4aef-9f72-a75a135a22d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_NemadjiTrailEnergyCenterMember_c901f0d0-e7eb-46bb-acb5-39c888e9bc40" xlink:href="ale-20210930.xsd#ale_NemadjiTrailEnergyCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_009da211-d407-4aef-9f72-a75a135a22d7" xlink:to="loc_ale_NemadjiTrailEnergyCenterMember_c901f0d0-e7eb-46bb-acb5-39c888e9bc40" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/RegulatoryMattersElectricRatesDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#RegulatoryMattersElectricRatesDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/RegulatoryMattersElectricRatesDetails" xlink:type="extended" id="i6fa37c2e46cb44d489d685c620ecfcf7_RegulatoryMattersElectricRatesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatedOperatingRevenueOther_c1e90837-1846-4805-91ab-963bb9114ab5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatedOperatingRevenueOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_RegulatedOperatingRevenueOther_c1e90837-1846-4805-91ab-963bb9114ab5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount_8d323693-7fdf-4ae5-b75b-4b54fea6a92f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount_8d323693-7fdf-4ae5-b75b-4b54fea6a92f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedRateIncreaseDecreasePercentage_a67630fc-9216-47b0-ae5c-e70687bf11ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedRateIncreaseDecreasePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesRequestedRateIncreaseDecreasePercentage_a67630fc-9216-47b0-ae5c-e70687bf11ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInterimRateIncreaseDecreaseAmount_d14b13b3-5917-4906-88de-cc853a8fdc9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInterimRateIncreaseDecreaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesInterimRateIncreaseDecreaseAmount_d14b13b3-5917-4906-88de-cc853a8fdc9d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage_6d1c21b8-63d1-4f9d-b18b-1d547af96049" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage_6d1c21b8-63d1-4f9d-b18b-1d547af96049" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage_0c437a58-d85b-4ff8-aa88-02ea56fef0e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage_0c437a58-d85b-4ff8-aa88-02ea56fef0e9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ProposedOngoingCustomerRateIncrease_7b0f9545-5db2-4245-ab72-08f9b2c575f3" xlink:href="ale-20210930.xsd#ale_ProposedOngoingCustomerRateIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_ale_ProposedOngoingCustomerRateIncrease_7b0f9545-5db2-4245-ab72-08f9b2c575f3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInterimRateIncreaseDecreasePercentage_12b1e033-6dac-4d7c-9f15-3fb0569b190d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInterimRateIncreaseDecreasePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesInterimRateIncreaseDecreasePercentage_12b1e033-6dac-4d7c-9f15-3fb0569b190d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_PublicUtilitiesReserveForInterimRates_b4aac4c6-91ec-4d38-bb67-a63739dc4240" xlink:href="ale-20210930.xsd#ale_PublicUtilitiesReserveForInterimRates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_ale_PublicUtilitiesReserveForInterimRates_b4aac4c6-91ec-4d38-bb67-a63739dc4240" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ForcedOutageCosts_53ca302f-d756-4c13-80bb-3084d1d69e0c" xlink:href="ale-20210930.xsd#ale_ForcedOutageCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_ale_ForcedOutageCosts_53ca302f-d756-4c13-80bb-3084d1d69e0c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_EstimatedAnnualReductionToRevenueDueToIdledCustomers_cce8be02-2037-4bd3-b8cc-dc9127028bbd" xlink:href="ale-20210930.xsd#ale_EstimatedAnnualReductionToRevenueDueToIdledCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_ale_EstimatedAnnualReductionToRevenueDueToIdledCustomers_cce8be02-2037-4bd3-b8cc-dc9127028bbd" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_EstimatedMarketValueReservoirLandToBeSold_92ecf294-f39b-4173-a8e2-1c9cda651bac" xlink:href="ale-20210930.xsd#ale_EstimatedMarketValueReservoirLandToBeSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_ale_EstimatedMarketValueReservoirLandToBeSold_92ecf294-f39b-4173-a8e2-1c9cda651bac" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AdministrativeLawJudgeRecommendedRefund_4505ea48-dcd0-4dd0-9e16-ceaff7f02c31" xlink:href="ale-20210930.xsd#ale_AdministrativeLawJudgeRecommendedRefund"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_ale_AdministrativeLawJudgeRecommendedRefund_4505ea48-dcd0-4dd0-9e16-ceaff7f02c31" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_f2ef7528-1e0e-4fd9-b2b0-fefcb16b8b5b" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RateTypeAxis_06ab3828-ec17-43c1-8239-d36607b81a60" xlink:href="ale-20210930.xsd#ale_RateTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:to="loc_ale_RateTypeAxis_06ab3828-ec17-43c1-8239-d36607b81a60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RateInformationByTypeDomain_06ab3828-ec17-43c1-8239-d36607b81a60_default" xlink:href="ale-20210930.xsd#ale_RateInformationByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_RateTypeAxis_06ab3828-ec17-43c1-8239-d36607b81a60" xlink:to="loc_ale_RateInformationByTypeDomain_06ab3828-ec17-43c1-8239-d36607b81a60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RateInformationByTypeDomain_fd5e3094-b6b1-4f34-95c7-69f1ae49615d" xlink:href="ale-20210930.xsd#ale_RateInformationByTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_RateTypeAxis_06ab3828-ec17-43c1-8239-d36607b81a60" xlink:to="loc_ale_RateInformationByTypeDomain_fd5e3094-b6b1-4f34-95c7-69f1ae49615d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ElectricRatesMember_47f3494e-7367-4e07-9ed9-805a0503acdb" xlink:href="ale-20210930.xsd#ale_ElectricRatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_RateInformationByTypeDomain_fd5e3094-b6b1-4f34-95c7-69f1ae49615d" xlink:to="loc_ale_ElectricRatesMember_47f3494e-7367-4e07-9ed9-805a0503acdb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyAxis_bec8c696-1902-4ca6-b1a0-03f16baf0261" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:to="loc_us-gaap_RegulatoryAgencyAxis_bec8c696-1902-4ca6-b1a0-03f16baf0261" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_bec8c696-1902-4ca6-b1a0-03f16baf0261_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_bec8c696-1902-4ca6-b1a0-03f16baf0261" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_bec8c696-1902-4ca6-b1a0-03f16baf0261_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_f2e30b74-626b-4ae0-a36f-83ad5e7796f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_bec8c696-1902-4ca6-b1a0-03f16baf0261" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_f2e30b74-626b-4ae0-a36f-83ad5e7796f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MPUCMember_2d4a6979-23e8-49ae-a593-801118647892" xlink:href="ale-20210930.xsd#ale_MPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_f2e30b74-626b-4ae0-a36f-83ad5e7796f2" xlink:to="loc_ale_MPUCMember_2d4a6979-23e8-49ae-a593-801118647892" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_a02ee45c-2c46-46ec-953c-7596318b8525" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_a02ee45c-2c46-46ec-953c-7596318b8525" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_a02ee45c-2c46-46ec-953c-7596318b8525_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_a02ee45c-2c46-46ec-953c-7596318b8525" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_a02ee45c-2c46-46ec-953c-7596318b8525_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_a02ee45c-2c46-46ec-953c-7596318b8525" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CurrentCostRecoveryRiderMember_0e6fdd34-3485-4334-9b6f-55c9255aaf23" xlink:href="ale-20210930.xsd#ale_CurrentCostRecoveryRiderMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_CurrentCostRecoveryRiderMember_0e6fdd34-3485-4334-9b6f-55c9255aaf23" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_A2020MinnesotaGeneralRateReviewMember_98e9b769-16e1-40c4-af1b-0bb6874349ff" xlink:href="ale-20210930.xsd#ale_A2020MinnesotaGeneralRateReviewMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_A2020MinnesotaGeneralRateReviewMember_98e9b769-16e1-40c4-af1b-0bb6874349ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CIPConsolidatedFilingMember_2ce1f469-bcf2-47e5-8726-3be3ed980b1f" xlink:href="ale-20210930.xsd#ale_CIPConsolidatedFilingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_CIPConsolidatedFilingMember_2ce1f469-bcf2-47e5-8726-3be3ed980b1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_FuelAdjustmentClauseFilingMember_6b8e8f19-8b06-4dba-9d88-33e3d0a789c5" xlink:href="ale-20210930.xsd#ale_FuelAdjustmentClauseFilingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_FuelAdjustmentClauseFilingMember_6b8e8f19-8b06-4dba-9d88-33e3d0a789c5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_COVID19RelatedDeferredAccountingMember_6f669dc0-2c9f-423e-b9f8-f65e1b46728d" xlink:href="ale-20210930.xsd#ale_COVID19RelatedDeferredAccountingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_COVID19RelatedDeferredAccountingMember_6f669dc0-2c9f-423e-b9f8-f65e1b46728d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_A2022MinnesotaGeneralRateReviewMember_c4c9075d-924f-4fe3-a896-877248e742fc" xlink:href="ale-20210930.xsd#ale_A2022MinnesotaGeneralRateReviewMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_A2022MinnesotaGeneralRateReviewMember_c4c9075d-924f-4fe3-a896-877248e742fc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerLandSalesMember_063554e6-0c39-4190-bad2-d5d5b8eec734" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerLandSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_09846e52-b0a0-4c73-85ea-fb466e8860c8" xlink:to="loc_ale_MinnesotaPowerLandSalesMember_063554e6-0c39-4190-bad2-d5d5b8eec734" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_af5f97cf-624f-4f6e-804f-cff89dc56922" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:to="loc_dei_LegalEntityAxis_af5f97cf-624f-4f6e-804f-cff89dc56922" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_af5f97cf-624f-4f6e-804f-cff89dc56922_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_af5f97cf-624f-4f6e-804f-cff89dc56922" xlink:to="loc_dei_EntityDomain_af5f97cf-624f-4f6e-804f-cff89dc56922_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_9e940deb-1596-4644-ae9d-7399cdcd5ff7" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_af5f97cf-624f-4f6e-804f-cff89dc56922" xlink:to="loc_dei_EntityDomain_9e940deb-1596-4644-ae9d-7399cdcd5ff7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_3c459e9c-d9c6-4630-8519-5746e85c3458" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_9e940deb-1596-4644-ae9d-7399cdcd5ff7" xlink:to="loc_ale_MinnesotaPowerMember_3c459e9c-d9c6-4630-8519-5746e85c3458" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RetailCustomersMember_2eb8b5bc-92d5-493b-a49d-6868fc4550d3" xlink:href="ale-20210930.xsd#ale_RetailCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_9e940deb-1596-4644-ae9d-7399cdcd5ff7" xlink:to="loc_ale_RetailCustomersMember_2eb8b5bc-92d5-493b-a49d-6868fc4550d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CustomerClassAxis_9f38d853-8e45-4ced-9bc1-ccab2b7b6946" xlink:href="ale-20210930.xsd#ale_CustomerClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:to="loc_ale_CustomerClassAxis_9f38d853-8e45-4ced-9bc1-ccab2b7b6946" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CustomerClassDomain_9f38d853-8e45-4ced-9bc1-ccab2b7b6946_default" xlink:href="ale-20210930.xsd#ale_CustomerClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_CustomerClassAxis_9f38d853-8e45-4ced-9bc1-ccab2b7b6946" xlink:to="loc_ale_CustomerClassDomain_9f38d853-8e45-4ced-9bc1-ccab2b7b6946_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CustomerClassDomain_c5a9e612-004d-4c6a-ba10-f7d9fdde54a7" xlink:href="ale-20210930.xsd#ale_CustomerClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_CustomerClassAxis_9f38d853-8e45-4ced-9bc1-ccab2b7b6946" xlink:to="loc_ale_CustomerClassDomain_c5a9e612-004d-4c6a-ba10-f7d9fdde54a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RetailCustomersMember_178a4b8b-49c7-42eb-ba1e-a266e2455daa" xlink:href="ale-20210930.xsd#ale_RetailCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_CustomerClassDomain_c5a9e612-004d-4c6a-ba10-f7d9fdde54a7" xlink:to="loc_ale_RetailCustomersMember_178a4b8b-49c7-42eb-ba1e-a266e2455daa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_fb5a08d6-2b54-4f56-b465-bcaeb4d8a157" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e115598d-3ebc-4bb7-a1e9-e2c33ec64bfa" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_fb5a08d6-2b54-4f56-b465-bcaeb4d8a157" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_fb5a08d6-2b54-4f56-b465-bcaeb4d8a157_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_fb5a08d6-2b54-4f56-b465-bcaeb4d8a157" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_fb5a08d6-2b54-4f56-b465-bcaeb4d8a157_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_d6297d5a-0c63-4103-ac0d-62003aadaba3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_fb5a08d6-2b54-4f56-b465-bcaeb4d8a157" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_d6297d5a-0c63-4103-ac0d-62003aadaba3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_a8f56831-1dee-411d-adf3-47f2056ebb80" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_d6297d5a-0c63-4103-ac0d-62003aadaba3" xlink:to="loc_us-gaap_SubsequentEventMember_a8f56831-1dee-411d-adf3-47f2056ebb80" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/RegulatoryMattersIntegratedResourcePlanDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#RegulatoryMattersIntegratedResourcePlanDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/RegulatoryMattersIntegratedResourcePlanDetails" xlink:type="extended" id="i7cd8ca70e5bd4cc991ffa4b24ede0c99_RegulatoryMattersIntegratedResourcePlanDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_c684c4ab-3355-4786-ae71-f3b182a072d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AnticipatedAdditionalGeneratingCapacityMW_339735f4-1550-4780-a563-fc689e0c52bd" xlink:href="ale-20210930.xsd#ale_AnticipatedAdditionalGeneratingCapacityMW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_c684c4ab-3355-4786-ae71-f3b182a072d1" xlink:to="loc_ale_AnticipatedAdditionalGeneratingCapacityMW_339735f4-1550-4780-a563-fc689e0c52bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a6e9a635-d740-47ce-9910-17856dfbd981" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_c684c4ab-3355-4786-ae71-f3b182a072d1" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a6e9a635-d740-47ce-9910-17856dfbd981" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeAxis_4fbb97c9-36d8-4f9a-adde-82ed4f8997ed" xlink:href="ale-20210930.xsd#ale_GenerationTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a6e9a635-d740-47ce-9910-17856dfbd981" xlink:to="loc_ale_GenerationTypeAxis_4fbb97c9-36d8-4f9a-adde-82ed4f8997ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_4fbb97c9-36d8-4f9a-adde-82ed4f8997ed_default" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GenerationTypeAxis_4fbb97c9-36d8-4f9a-adde-82ed4f8997ed" xlink:to="loc_ale_GenerationTypeDomain_4fbb97c9-36d8-4f9a-adde-82ed4f8997ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_66c1c53e-9057-451a-8cb2-33424ddc7eaf" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GenerationTypeAxis_4fbb97c9-36d8-4f9a-adde-82ed4f8997ed" xlink:to="loc_ale_GenerationTypeDomain_66c1c53e-9057-451a-8cb2-33424ddc7eaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RenewableGenerationMember_584ce197-f264-4938-b3bb-af4e172e319d" xlink:href="ale-20210930.xsd#ale_RenewableGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GenerationTypeDomain_66c1c53e-9057-451a-8cb2-33424ddc7eaf" xlink:to="loc_ale_RenewableGenerationMember_584ce197-f264-4938-b3bb-af4e172e319d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_c32b59dc-213b-4683-82dc-f909c01ef5d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a6e9a635-d740-47ce-9910-17856dfbd981" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_c32b59dc-213b-4683-82dc-f909c01ef5d0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_c32b59dc-213b-4683-82dc-f909c01ef5d0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_c32b59dc-213b-4683-82dc-f909c01ef5d0" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_c32b59dc-213b-4683-82dc-f909c01ef5d0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_9aaf83cf-ccab-404c-8296-02477dc48c5a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_c32b59dc-213b-4683-82dc-f909c01ef5d0" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_9aaf83cf-ccab-404c-8296-02477dc48c5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MPUCMember_927ae8be-9971-41f2-b38b-de93b7ae6751" xlink:href="ale-20210930.xsd#ale_MPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_9aaf83cf-ccab-404c-8296-02477dc48c5a" xlink:to="loc_ale_MPUCMember_927ae8be-9971-41f2-b38b-de93b7ae6751" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_A2021IntegratedResourcePlanMember_d3b7d533-560e-4c29-9d71-b5ca4cb5607b" xlink:href="ale-20210930.xsd#ale_A2021IntegratedResourcePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_9aaf83cf-ccab-404c-8296-02477dc48c5a" xlink:to="loc_ale_A2021IntegratedResourcePlanMember_d3b7d533-560e-4c29-9d71-b5ca4cb5607b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyAxis_d1ff7a70-5cf1-4bed-b2c6-176267cf2fb5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a6e9a635-d740-47ce-9910-17856dfbd981" xlink:to="loc_us-gaap_RegulatoryAgencyAxis_d1ff7a70-5cf1-4bed-b2c6-176267cf2fb5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_d1ff7a70-5cf1-4bed-b2c6-176267cf2fb5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_d1ff7a70-5cf1-4bed-b2c6-176267cf2fb5" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_d1ff7a70-5cf1-4bed-b2c6-176267cf2fb5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_2cc2e8bd-220b-4a68-8330-23d2d945146d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_d1ff7a70-5cf1-4bed-b2c6-176267cf2fb5" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_2cc2e8bd-220b-4a68-8330-23d2d945146d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MPUCMember_0ced3be0-d957-4497-92af-06ca3585165a" xlink:href="ale-20210930.xsd#ale_MPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_2cc2e8bd-220b-4a68-8330-23d2d945146d" xlink:to="loc_ale_MPUCMember_0ced3be0-d957-4497-92af-06ca3585165a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/RegulatoryMattersNemadjiTrailEnergyCenterDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#RegulatoryMattersNemadjiTrailEnergyCenterDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/RegulatoryMattersNemadjiTrailEnergyCenterDetails" xlink:type="extended" id="i61487c50345948e99705a1b8796109aa_RegulatoryMattersNemadjiTrailEnergyCenterDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_e4f733b6-27ae-4d32-b0f4-28c5ae2ccbfe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingCapacityJointlyOwnedMW_4f7cbb81-d5e3-4abe-acd3-127a90aace63" xlink:href="ale-20210930.xsd#ale_GeneratingCapacityJointlyOwnedMW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_e4f733b6-27ae-4d32-b0f4-28c5ae2ccbfe" xlink:to="loc_ale_GeneratingCapacityJointlyOwnedMW_4f7cbb81-d5e3-4abe-acd3-127a90aace63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased_9ab85b8c-5656-4cd8-9149-9f4988127e7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_e4f733b6-27ae-4d32-b0f4-28c5ae2ccbfe" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased_9ab85b8c-5656-4cd8-9149-9f4988127e7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_e4f733b6-27ae-4d32-b0f4-28c5ae2ccbfe" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeAxis_78080fac-fe8d-4ceb-bcf4-f8abf1416a55" xlink:href="ale-20210930.xsd#ale_GenerationTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:to="loc_ale_GenerationTypeAxis_78080fac-fe8d-4ceb-bcf4-f8abf1416a55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_78080fac-fe8d-4ceb-bcf4-f8abf1416a55_default" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GenerationTypeAxis_78080fac-fe8d-4ceb-bcf4-f8abf1416a55" xlink:to="loc_ale_GenerationTypeDomain_78080fac-fe8d-4ceb-bcf4-f8abf1416a55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_99f08786-6a88-492f-a692-497802defcb8" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GenerationTypeAxis_78080fac-fe8d-4ceb-bcf4-f8abf1416a55" xlink:to="loc_ale_GenerationTypeDomain_99f08786-6a88-492f-a692-497802defcb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NaturalGasProcessingPlantMember_3bc0edbb-a3f3-46cd-880c-e3b66607d124" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NaturalGasProcessingPlantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GenerationTypeDomain_99f08786-6a88-492f-a692-497802defcb8" xlink:to="loc_us-gaap_NaturalGasProcessingPlantMember_3bc0edbb-a3f3-46cd-880c-e3b66607d124" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b7635d76-dadc-4b84-86e8-990ad5f139b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b7635d76-dadc-4b84-86e8-990ad5f139b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_b7635d76-dadc-4b84-86e8-990ad5f139b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b7635d76-dadc-4b84-86e8-990ad5f139b9" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_b7635d76-dadc-4b84-86e8-990ad5f139b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_83359da6-ee21-4ba6-b7d6-d4fca1e36bbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b7635d76-dadc-4b84-86e8-990ad5f139b9" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_83359da6-ee21-4ba6-b7d6-d4fca1e36bbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_NaturalGasPPAMember_f6494bf9-6cbc-4ad0-bf57-ee2670d70c10" xlink:href="ale-20210930.xsd#ale_NaturalGasPPAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_83359da6-ee21-4ba6-b7d6-d4fca1e36bbd" xlink:to="loc_ale_NaturalGasPPAMember_f6494bf9-6cbc-4ad0-bf57-ee2670d70c10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_ad03bffa-5712-4647-8716-dac37308c97f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_ad03bffa-5712-4647-8716-dac37308c97f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_ad03bffa-5712-4647-8716-dac37308c97f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_ad03bffa-5712-4647-8716-dac37308c97f" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_ad03bffa-5712-4647-8716-dac37308c97f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_f7ac847e-2f9a-43e0-965a-8880e7bd9648" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_ad03bffa-5712-4647-8716-dac37308c97f" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_f7ac847e-2f9a-43e0-965a-8880e7bd9648" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ResourcePackageMember_f9750012-fb3e-495d-8c56-1dbb2e136ed7" xlink:href="ale-20210930.xsd#ale_ResourcePackageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_f7ac847e-2f9a-43e0-965a-8880e7bd9648" xlink:to="loc_ale_ResourcePackageMember_f9750012-fb3e-495d-8c56-1dbb2e136ed7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyAxis_497cddc4-8def-4583-9a2d-7e116b5c69f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:to="loc_us-gaap_RegulatoryAgencyAxis_497cddc4-8def-4583-9a2d-7e116b5c69f2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_497cddc4-8def-4583-9a2d-7e116b5c69f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_497cddc4-8def-4583-9a2d-7e116b5c69f2" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_497cddc4-8def-4583-9a2d-7e116b5c69f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_1f12b54e-10d1-4504-bd9c-f49f0911f872" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_497cddc4-8def-4583-9a2d-7e116b5c69f2" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_1f12b54e-10d1-4504-bd9c-f49f0911f872" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MPUCMember_0a7bbb48-28cf-4d59-9940-06c7678fbd33" xlink:href="ale-20210930.xsd#ale_MPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_1f12b54e-10d1-4504-bd9c-f49f0911f872" xlink:to="loc_ale_MPUCMember_0a7bbb48-28cf-4d59-9940-06c7678fbd33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_a71c5050-f98a-4651-b5a2-e134e402ad01" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:to="loc_dei_LegalEntityAxis_a71c5050-f98a-4651-b5a2-e134e402ad01" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_a71c5050-f98a-4651-b5a2-e134e402ad01_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_a71c5050-f98a-4651-b5a2-e134e402ad01" xlink:to="loc_dei_EntityDomain_a71c5050-f98a-4651-b5a2-e134e402ad01_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_70e3a78a-d2ea-4278-a536-8640003b2657" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_a71c5050-f98a-4651-b5a2-e134e402ad01" xlink:to="loc_dei_EntityDomain_70e3a78a-d2ea-4278-a536-8640003b2657" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_aec501ae-5576-4bce-962b-dfbe9dd39540" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_70e3a78a-d2ea-4278-a536-8640003b2657" xlink:to="loc_ale_MinnesotaPowerMember_aec501ae-5576-4bce-962b-dfbe9dd39540" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityAxisAxis_81278639-708b-4414-9bc7-58d0a6936876" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityAxisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_bdf21381-8a86-43bd-920e-a40c21b9e1ba" xlink:to="loc_ale_GeneratingFacilityAxisAxis_81278639-708b-4414-9bc7-58d0a6936876" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_81278639-708b-4414-9bc7-58d0a6936876_default" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GeneratingFacilityAxisAxis_81278639-708b-4414-9bc7-58d0a6936876" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_81278639-708b-4414-9bc7-58d0a6936876_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_2b3bd106-1e2e-44ae-837f-81c8d57ef21c" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GeneratingFacilityAxisAxis_81278639-708b-4414-9bc7-58d0a6936876" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_2b3bd106-1e2e-44ae-837f-81c8d57ef21c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_NemadjiTrailEnergyCenterMember_3efbb376-c7ef-4e10-bb7e-32409d3330a2" xlink:href="ale-20210930.xsd#ale_NemadjiTrailEnergyCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_2b3bd106-1e2e-44ae-837f-81c8d57ef21c" xlink:to="loc_ale_NemadjiTrailEnergyCenterMember_3efbb376-c7ef-4e10-bb7e-32409d3330a2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/RegulatoryMattersVersoCorporationDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#RegulatoryMattersVersoCorporationDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/RegulatoryMattersVersoCorporationDetails" xlink:type="extended" id="i2e0e8bd25a914196bcfcd6283631f5cf_RegulatoryMattersVersoCorporationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_a0784e7a-ad80-4079-986c-266c44965b5e" xlink:href="ale-20210930.xsd#ale_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_16aabb01-c43e-41bf-88a9-f03fe2297c17" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_a0784e7a-ad80-4079-986c-266c44965b5e" xlink:to="loc_us-gaap_AccountsReceivableNet_16aabb01-c43e-41bf-88a9-f03fe2297c17" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_df0fc8c2-3e4c-47c6-8b1a-91409f20db1c" xlink:href="ale-20210930.xsd#ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_a0784e7a-ad80-4079-986c-266c44965b5e" xlink:to="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_df0fc8c2-3e4c-47c6-8b1a-91409f20db1c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ServiceAgreementTypeAxis_8097b561-9086-417e-8acf-5f46638dbe55" xlink:href="ale-20210930.xsd#ale_ServiceAgreementTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_df0fc8c2-3e4c-47c6-8b1a-91409f20db1c" xlink:to="loc_ale_ServiceAgreementTypeAxis_8097b561-9086-417e-8acf-5f46638dbe55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ServiceAgreementTypeDomain_8097b561-9086-417e-8acf-5f46638dbe55_default" xlink:href="ale-20210930.xsd#ale_ServiceAgreementTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_ServiceAgreementTypeAxis_8097b561-9086-417e-8acf-5f46638dbe55" xlink:to="loc_ale_ServiceAgreementTypeDomain_8097b561-9086-417e-8acf-5f46638dbe55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ServiceAgreementTypeDomain_e09e485a-6e33-4059-a3d7-8978ba6fa5a2" xlink:href="ale-20210930.xsd#ale_ServiceAgreementTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_ServiceAgreementTypeAxis_8097b561-9086-417e-8acf-5f46638dbe55" xlink:to="loc_ale_ServiceAgreementTypeDomain_e09e485a-6e33-4059-a3d7-8978ba6fa5a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ElectricServicesAgreementMember_4766ddec-0eb2-46e1-84bd-e62a093a0965" xlink:href="ale-20210930.xsd#ale_ElectricServicesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ServiceAgreementTypeDomain_e09e485a-6e33-4059-a3d7-8978ba6fa5a2" xlink:to="loc_ale_ElectricServicesAgreementMember_4766ddec-0eb2-46e1-84bd-e62a093a0965" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SteamServicesAgreementMember_2c40bc37-b6ca-4199-a9b1-c5c8510d7a8a" xlink:href="ale-20210930.xsd#ale_SteamServicesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_ServiceAgreementTypeDomain_e09e485a-6e33-4059-a3d7-8978ba6fa5a2" xlink:to="loc_ale_SteamServicesAgreementMember_2c40bc37-b6ca-4199-a9b1-c5c8510d7a8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_95246a1d-c307-4c22-8edd-9366865cb7e7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_df0fc8c2-3e4c-47c6-8b1a-91409f20db1c" xlink:to="loc_srt_MajorCustomersAxis_95246a1d-c307-4c22-8edd-9366865cb7e7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_95246a1d-c307-4c22-8edd-9366865cb7e7_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_95246a1d-c307-4c22-8edd-9366865cb7e7" xlink:to="loc_srt_NameOfMajorCustomerDomain_95246a1d-c307-4c22-8edd-9366865cb7e7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_6c8e29c3-3cfa-472d-b954-d9e868acf5c2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_95246a1d-c307-4c22-8edd-9366865cb7e7" xlink:to="loc_srt_NameOfMajorCustomerDomain_6c8e29c3-3cfa-472d-b954-d9e868acf5c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_VersoCorporationMember_548a6937-6783-4340-b588-38d458597ce6" xlink:href="ale-20210930.xsd#ale_VersoCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_6c8e29c3-3cfa-472d-b954-d9e868acf5c2" xlink:to="loc_ale_VersoCorporationMember_548a6937-6783-4340-b588-38d458597ce6" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/RegulatoryMattersRegulatoryAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#RegulatoryMattersRegulatoryAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/RegulatoryMattersRegulatoryAssetsandLiabilitiesDetails" xlink:type="extended" id="icacb63ef923f4e01b486fb589958c128_RegulatoryMattersRegulatoryAssetsandLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:href="ale-20210930.xsd#ale_RegulatoryAssetsAndLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypesOfNetRegulatoryAssetsEarningReturns_4114641a-5f8f-4deb-91f9-5a9214619a01" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypesOfNetRegulatoryAssetsEarningReturns"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:to="loc_us-gaap_TypesOfNetRegulatoryAssetsEarningReturns_4114641a-5f8f-4deb-91f9-5a9214619a01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsNoncurrent_a982186f-7452-4b5f-b9c5-d9eb056bc519" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:to="loc_us-gaap_RegulatoryAssetsNoncurrent_a982186f-7452-4b5f-b9c5-d9eb056bc519" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityCurrent_f3546ace-69a8-4ace-aaa5-3e168ed25f33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:to="loc_us-gaap_RegulatoryLiabilityCurrent_f3546ace-69a8-4ace-aaa5-3e168ed25f33" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityNoncurrent_8deede8c-0490-40e0-8d9e-3d825c75acd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:to="loc_us-gaap_RegulatoryLiabilityNoncurrent_8deede8c-0490-40e0-8d9e-3d825c75acd5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilities_121e4b4a-e158-40ec-bb86-75b9b6879217" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:to="loc_us-gaap_RegulatoryLiabilities_121e4b4a-e158-40ec-bb86-75b9b6879217" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_5322df00-884f-4609-bbda-b8833cb44a8d" xlink:href="ale-20210930.xsd#ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ale_RegulatoryAssetsAndLiabilitiesLineItems_92f0a532-46b3-433f-af0d-0f177216cefd" xlink:to="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_5322df00-884f-4609-bbda-b8833cb44a8d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_07ab9696-8509-46ec-a6d1-78586dff605c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_5322df00-884f-4609-bbda-b8833cb44a8d" xlink:to="loc_us-gaap_RegulatoryAssetAxis_07ab9696-8509-46ec-a6d1-78586dff605c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_07ab9696-8509-46ec-a6d1-78586dff605c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_07ab9696-8509-46ec-a6d1-78586dff605c" xlink:to="loc_us-gaap_RegulatoryAssetDomain_07ab9696-8509-46ec-a6d1-78586dff605c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_07ab9696-8509-46ec-a6d1-78586dff605c" xlink:to="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_4354e7de-7774-4c59-83c7-5847f3c20a8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_4354e7de-7774-4c59-83c7-5847f3c20a8d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxChargesMember_f00687d9-7902-49de-94b7-ce36b47fc050" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxChargesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_us-gaap_DeferredIncomeTaxChargesMember_f00687d9-7902-49de-94b7-ce36b47fc050" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CostRecoveryRidersMember_887138d4-fa20-49dc-9e96-77775ab01751" xlink:href="ale-20210930.xsd#ale_CostRecoveryRidersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_ale_CostRecoveryRidersMember_887138d4-fa20-49dc-9e96-77775ab01751" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRetirementObligationCostsMember_2d831079-86d5-43ea-b5f3-e599d8788de3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetRetirementObligationCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_us-gaap_AssetRetirementObligationCostsMember_2d831079-86d5-43ea-b5f3-e599d8788de3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ManufacturedGasPlantMember_fb1a3b17-7beb-4359-8ccf-cd24ff9d9cad" xlink:href="ale-20210930.xsd#ale_ManufacturedGasPlantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_ale_ManufacturedGasPlantMember_fb1a3b17-7beb-4359-8ccf-cd24ff9d9cad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_Boswell12Member_11d3842b-5e6e-4f8f-8a80-95d41abccab6" xlink:href="ale-20210930.xsd#ale_Boswell12Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_ale_Boswell12Member_11d3842b-5e6e-4f8f-8a80-95d41abccab6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MedicarePartDRegulatoryAssetMember_ce1b96d4-1311-4208-842a-11589827c144" xlink:href="ale-20210930.xsd#ale_MedicarePartDRegulatoryAssetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_ale_MedicarePartDRegulatoryAssetMember_ce1b96d4-1311-4208-842a-11589827c144" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherRegulatoryAssetsLiabilitiesMember_12d29432-fd5c-4303-a72c-6e7c5d251736" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherRegulatoryAssetsLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_us-gaap_OtherRegulatoryAssetsLiabilitiesMember_12d29432-fd5c-4303-a72c-6e7c5d251736" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_FuelAdjustmentClauseMember_bad396dc-cba2-42b5-8881-ed49bf4ed319" xlink:href="ale-20210930.xsd#ale_FuelAdjustmentClauseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_ale_FuelAdjustmentClauseMember_bad396dc-cba2-42b5-8881-ed49bf4ed319" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryClauseRevenuesUnderRecoveredMember_9a2fd794-4fce-4472-9dfe-15f3c1083a98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryClauseRevenuesUnderRecoveredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_5a6bfd96-1729-46d0-8401-92f8d59669e5" xlink:to="loc_us-gaap_RegulatoryClauseRevenuesUnderRecoveredMember_9a2fd794-4fce-4472-9dfe-15f3c1083a98" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityAxis_3c91cf17-e5e3-40bd-afa2-ae4a4336e1f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_5322df00-884f-4609-bbda-b8833cb44a8d" xlink:to="loc_us-gaap_RegulatoryLiabilityAxis_3c91cf17-e5e3-40bd-afa2-ae4a4336e1f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_3c91cf17-e5e3-40bd-afa2-ae4a4336e1f4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_3c91cf17-e5e3-40bd-afa2-ae4a4336e1f4" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_3c91cf17-e5e3-40bd-afa2-ae4a4336e1f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_3c91cf17-e5e3-40bd-afa2-ae4a4336e1f4" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryClauseRevenuesUnderRecoveredMember_fed402ec-c66e-4d69-9c4a-e7512e00a0c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryClauseRevenuesUnderRecoveredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_us-gaap_RegulatoryClauseRevenuesUnderRecoveredMember_fed402ec-c66e-4d69-9c4a-e7512e00a0c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_PublicUtilitiesReserveForInterimRates_9531348d-691e-460c-90db-d1e62074098a" xlink:href="ale-20210930.xsd#ale_PublicUtilitiesReserveForInterimRates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_PublicUtilitiesReserveForInterimRates_9531348d-691e-460c-90db-d1e62074098a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_TransmissionFormulaRatesMember_95bd3f49-1fe0-471b-be58-2004a36197c7" xlink:href="ale-20210930.xsd#ale_TransmissionFormulaRatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_TransmissionFormulaRatesMember_95bd3f49-1fe0-471b-be58-2004a36197c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxChargesMember_da8f545d-3d43-4eed-b2ce-205585f15766" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxChargesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_us-gaap_DeferredIncomeTaxChargesMember_da8f545d-3d43-4eed-b2ce-205585f15766" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_WholesaleAndRetailContraAfudcMember_261fa5d8-dd27-4d2d-a5fc-3c547d48501b" xlink:href="ale-20210930.xsd#ale_WholesaleAndRetailContraAfudcMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_WholesaleAndRetailContraAfudcMember_261fa5d8-dd27-4d2d-a5fc-3c547d48501b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RemovalCostsMember_cf0d8a01-bf3b-44eb-87d8-0e791c4e4811" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RemovalCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_us-gaap_RemovalCostsMember_cf0d8a01-bf3b-44eb-87d8-0e791c4e4811" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_bf227b42-3cdc-4f30-8f37-8d7d1554a8a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_bf227b42-3cdc-4f30-8f37-8d7d1554a8a8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_NorthDakotaInvestmentTaxCreditsSubjecttoRefundMember_63f53378-30c7-40f4-a462-1dd6280f4b9d" xlink:href="ale-20210930.xsd#ale_NorthDakotaInvestmentTaxCreditsSubjecttoRefundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_NorthDakotaInvestmentTaxCreditsSubjecttoRefundMember_63f53378-30c7-40f4-a462-1dd6280f4b9d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CIPFinancialIncentiveMember_050171ae-8f95-42c0-9a15-8f66b99625e2" xlink:href="ale-20210930.xsd#ale_CIPFinancialIncentiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_CIPFinancialIncentiveMember_050171ae-8f95-42c0-9a15-8f66b99625e2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CostRecoveryRidersMember_aba3898b-1417-4209-a506-3108f9492dd5" xlink:href="ale-20210930.xsd#ale_CostRecoveryRidersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_CostRecoveryRidersMember_aba3898b-1417-4209-a506-3108f9492dd5" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherRegulatoryAssetsLiabilitiesMember_08181a68-a792-4ed2-9af1-da74710e49e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherRegulatoryAssetsLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_us-gaap_OtherRegulatoryAssetsLiabilitiesMember_08181a68-a792-4ed2-9af1-da74710e49e0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_FuelAdjustmentClauseMember_b17356f5-c53d-4d9f-ac70-049ec50ddaa5" xlink:href="ale-20210930.xsd#ale_FuelAdjustmentClauseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_b4aa4860-3e02-461e-80f6-c7550c64fcf4" xlink:to="loc_ale_FuelAdjustmentClauseMember_b17356f5-c53d-4d9f-ac70-049ec50ddaa5" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/EquityInvestmentsTables" xlink:type="simple" xlink:href="ale-20210930.xsd#EquityInvestmentsTables"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/EquityInvestmentsTables" xlink:type="extended" id="i3aab5fb326ca4a229f27b9529f390160_EquityInvestmentsTables">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_89224fba-334a-488e-9d19-2880f57bec46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsTextBlock_794edde1-ee05-4089-8dfb-c990c299bf9f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentsTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_89224fba-334a-488e-9d19-2880f57bec46" xlink:to="loc_us-gaap_EquityMethodInvestmentsTextBlock_794edde1-ee05-4089-8dfb-c990c299bf9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_6f20cbc1-62f5-40c4-823d-05a393582f51" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_89224fba-334a-488e-9d19-2880f57bec46" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_6f20cbc1-62f5-40c4-823d-05a393582f51" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_b58b3658-4d5e-4866-9295-907d3aa2985a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_6f20cbc1-62f5-40c4-823d-05a393582f51" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_b58b3658-4d5e-4866-9295-907d3aa2985a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_b58b3658-4d5e-4866-9295-907d3aa2985a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_b58b3658-4d5e-4866-9295-907d3aa2985a" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_b58b3658-4d5e-4866-9295-907d3aa2985a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_132cd1a9-2b97-48e5-b144-de3d3b47f205" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_b58b3658-4d5e-4866-9295-907d3aa2985a" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_132cd1a9-2b97-48e5-b144-de3d3b47f205" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ATCMember_61fe24b1-8f3a-4be2-bda0-d134fab12f5c" xlink:href="ale-20210930.xsd#ale_ATCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_132cd1a9-2b97-48e5-b144-de3d3b47f205" xlink:to="loc_ale_ATCMember_61fe24b1-8f3a-4be2-bda0-d134fab12f5c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_Nobles2Member_32e1698f-a877-4af9-a15d-b76f6db9bf6e" xlink:href="ale-20210930.xsd#ale_Nobles2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_132cd1a9-2b97-48e5-b144-de3d3b47f205" xlink:to="loc_ale_Nobles2Member_32e1698f-a877-4af9-a15d-b76f6db9bf6e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/EquityInvestmentsInvestmentinATCDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#EquityInvestmentsInvestmentinATCDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/EquityInvestmentsInvestmentinATCDetails" xlink:type="extended" id="i448653f0e4e9455e9b80424d47cf68e2_EquityInvestmentsInvestmentinATCDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_f52f4e06-65eb-4eef-975e-80f449e23295" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_f52f4e06-65eb-4eef-975e-80f449e23295" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:href="ale-20210930.xsd#ale_AlletesInvestmentInAtcRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_d6cd1065-06e1-4a74-9702-5810eb83c8f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:to="loc_us-gaap_EquityMethodInvestments_d6cd1065-06e1-4a74-9702-5810eb83c8f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_0e7f0c99-5c2f-4a32-80d9-8d6612cf1697" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_0e7f0c99-5c2f-4a32-80d9-8d6612cf1697" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_79d3250a-8cd1-4cd2-8a20-c5d3ca599b52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_79d3250a-8cd1-4cd2-8a20-c5d3ca599b52" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_4d8b311a-4d38-419c-a66a-e2f57c4e0720" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_4d8b311a-4d38-419c-a66a-e2f57c4e0720" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AmortizationfromtheRemeasurementofDeferredIncomeTaxesforEquityMethodInvestments_736f97ba-5033-4888-83e4-78e92df09332" xlink:href="ale-20210930.xsd#ale_AmortizationfromtheRemeasurementofDeferredIncomeTaxesforEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_AlletesInvestmentInAtcRollForward_49f3435a-dd87-45b7-a14a-27426dcadfeb" xlink:to="loc_ale_AmortizationfromtheRemeasurementofDeferredIncomeTaxesforEquityMethodInvestments_736f97ba-5033-4888-83e4-78e92df09332" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_6f17f8c3-c332-4552-a7eb-0ca3d4031efd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage_a0ff1052-dc71-4e9e-a8d3-b1734cafbeb6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage_a0ff1052-dc71-4e9e-a8d3-b1734cafbeb6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_EquityMethodInvestmentApprovedReturnonCommonEquityIncludingIncentiveAdder_d6301ce1-8a55-4374-9ffd-074a5d7747ff" xlink:href="ale-20210930.xsd#ale_EquityMethodInvestmentApprovedReturnonCommonEquityIncludingIncentiveAdder"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_ale_EquityMethodInvestmentApprovedReturnonCommonEquityIncludingIncentiveAdder_d6301ce1-8a55-4374-9ffd-074a5d7747ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ApproximateRefundForReversalOfFERCROEOrder_16041fea-d15f-4962-a24c-7306ea53e884" xlink:href="ale-20210930.xsd#ale_ApproximateRefundForReversalOfFERCROEOrder"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_ale_ApproximateRefundForReversalOfFERCROEOrder_16041fea-d15f-4962-a24c-7306ea53e884" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ApproximateRefundForReversalOfFERCROEOrderALLETEsProportionateShare_f67b10d1-3e09-4791-b4a0-067ad54aec95" xlink:href="ale-20210930.xsd#ale_ApproximateRefundForReversalOfFERCROEOrderALLETEsProportionateShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_ale_ApproximateRefundForReversalOfFERCROEOrderALLETEsProportionateShare_f67b10d1-3e09-4791-b4a0-067ad54aec95" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_df22bdb4-1323-4cea-bca4-fb5600483d97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_c102400c-b312-415f-b48b-0919845e8193" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_df22bdb4-1323-4cea-bca4-fb5600483d97" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_d3f3083f-0813-4009-81ed-38b0932b31d5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_df22bdb4-1323-4cea-bca4-fb5600483d97" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_d3f3083f-0813-4009-81ed-38b0932b31d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_d3f3083f-0813-4009-81ed-38b0932b31d5_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_d3f3083f-0813-4009-81ed-38b0932b31d5" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_d3f3083f-0813-4009-81ed-38b0932b31d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_1702f467-e8e6-4d70-93df-e67548994f27" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_d3f3083f-0813-4009-81ed-38b0932b31d5" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_1702f467-e8e6-4d70-93df-e67548994f27" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ATCMember_f77a490d-36da-47ff-861a-abd4d23c352e" xlink:href="ale-20210930.xsd#ale_ATCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_1702f467-e8e6-4d70-93df-e67548994f27" xlink:to="loc_ale_ATCMember_f77a490d-36da-47ff-861a-abd4d23c352e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_40033b16-7a94-4e23-965a-d8b1ba4b7517" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_df22bdb4-1323-4cea-bca4-fb5600483d97" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_40033b16-7a94-4e23-965a-d8b1ba4b7517" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_40033b16-7a94-4e23-965a-d8b1ba4b7517_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_40033b16-7a94-4e23-965a-d8b1ba4b7517" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_40033b16-7a94-4e23-965a-d8b1ba4b7517_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_e8ca0e98-8e09-4e60-9557-79232b03c835" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_40033b16-7a94-4e23-965a-d8b1ba4b7517" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_e8ca0e98-8e09-4e60-9557-79232b03c835" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/EquityInvestmentsInvestmentinNobles2Details" xlink:type="simple" xlink:href="ale-20210930.xsd#EquityInvestmentsInvestmentinNobles2Details"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/EquityInvestmentsInvestmentinNobles2Details" xlink:type="extended" id="i7ca5b470da5c4f2aa699ec609bd3962b_EquityInvestmentsInvestmentinNobles2Details">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_41e18c43-eb42-4e10-9b9f-62e5a771cd52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_41e18c43-eb42-4e10-9b9f-62e5a771cd52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingCapacityCounterpartyOwnedMW_c4c2a7da-2dc9-461a-a22b-13175590977d" xlink:href="ale-20210930.xsd#ale_GeneratingCapacityCounterpartyOwnedMW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_ale_GeneratingCapacityCounterpartyOwnedMW_c4c2a7da-2dc9-461a-a22b-13175590977d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_LongtermContractforPurchaseofElectricPowerTermofContractYears_f3c31f0c-d25e-4d3d-8a41-6450ac7562c7" xlink:href="ale-20210930.xsd#ale_LongtermContractforPurchaseofElectricPowerTermofContractYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_ale_LongtermContractforPurchaseofElectricPowerTermofContractYears_f3c31f0c-d25e-4d3d-8a41-6450ac7562c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_004dab67-5c1c-4ff8-aa22-5464c636ec13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_EquityMethodInvestments_004dab67-5c1c-4ff8-aa22-5464c636ec13" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_48eda0cd-13e8-4255-8782-2a086e327d36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_48eda0cd-13e8-4255-8782-2a086e327d36" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_3e36a6a1-b3cb-43cf-997e-46b8067f17da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_3e36a6a1-b3cb-43cf-997e-46b8067f17da" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_80252c0e-4ffd-4506-9abf-223c1c3a3470" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_80252c0e-4ffd-4506-9abf-223c1c3a3470" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_99025b4b-eba7-48e9-9050-e7c2586c434b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_99025b4b-eba7-48e9-9050-e7c2586c434b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_0a0c736f-a6f3-466b-bce0-17c64cef8188" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeAxis_1f9483e6-2a97-4770-9cad-941eb65222c5" xlink:href="ale-20210930.xsd#ale_GenerationTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:to="loc_ale_GenerationTypeAxis_1f9483e6-2a97-4770-9cad-941eb65222c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_1f9483e6-2a97-4770-9cad-941eb65222c5_default" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GenerationTypeAxis_1f9483e6-2a97-4770-9cad-941eb65222c5" xlink:to="loc_ale_GenerationTypeDomain_1f9483e6-2a97-4770-9cad-941eb65222c5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GenerationTypeDomain_dfbfc7bd-d8fe-413a-8b02-b1064549def9" xlink:href="ale-20210930.xsd#ale_GenerationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GenerationTypeAxis_1f9483e6-2a97-4770-9cad-941eb65222c5" xlink:to="loc_ale_GenerationTypeDomain_dfbfc7bd-d8fe-413a-8b02-b1064549def9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_WindTurbineGeneratorsMember_27ae2b4a-9706-4a87-9c4a-7b75e2c8223e" xlink:href="ale-20210930.xsd#ale_WindTurbineGeneratorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GenerationTypeDomain_dfbfc7bd-d8fe-413a-8b02-b1064549def9" xlink:to="loc_ale_WindTurbineGeneratorsMember_27ae2b4a-9706-4a87-9c4a-7b75e2c8223e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_090982aa-4a43-480f-a40c-d106be77980f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:to="loc_srt_CounterpartyNameAxis_090982aa-4a43-480f-a40c-d106be77980f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_090982aa-4a43-480f-a40c-d106be77980f_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_090982aa-4a43-480f-a40c-d106be77980f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_090982aa-4a43-480f-a40c-d106be77980f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a2e523d9-f58f-4cbc-893a-d60a4c1bcce4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_090982aa-4a43-480f-a40c-d106be77980f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a2e523d9-f58f-4cbc-893a-d60a4c1bcce4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_TenaskaMember_ad8e3671-3597-4f25-a447-e756b42568db" xlink:href="ale-20210930.xsd#ale_TenaskaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a2e523d9-f58f-4cbc-893a-d60a4c1bcce4" xlink:to="loc_ale_TenaskaMember_ad8e3671-3597-4f25-a447-e756b42568db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_76eb46d6-0313-4b57-a9a9-c9407a8ab46f" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:to="loc_dei_LegalEntityAxis_76eb46d6-0313-4b57-a9a9-c9407a8ab46f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_76eb46d6-0313-4b57-a9a9-c9407a8ab46f_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_76eb46d6-0313-4b57-a9a9-c9407a8ab46f" xlink:to="loc_dei_EntityDomain_76eb46d6-0313-4b57-a9a9-c9407a8ab46f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_8d757bd9-3ae4-4fd8-9762-10d5428d09f9" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_76eb46d6-0313-4b57-a9a9-c9407a8ab46f" xlink:to="loc_dei_EntityDomain_8d757bd9-3ae4-4fd8-9762-10d5428d09f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_5b125392-21fa-43ab-8995-db308d14e349" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_8d757bd9-3ae4-4fd8-9762-10d5428d09f9" xlink:to="loc_ale_MinnesotaPowerMember_5b125392-21fa-43ab-8995-db308d14e349" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_bac6c977-5879-4144-a6d9-9a0a06d5653f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_bac6c977-5879-4144-a6d9-9a0a06d5653f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_bac6c977-5879-4144-a6d9-9a0a06d5653f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_bac6c977-5879-4144-a6d9-9a0a06d5653f" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_bac6c977-5879-4144-a6d9-9a0a06d5653f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_ca093ba3-a318-4926-87e4-1756b29ed646" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_bac6c977-5879-4144-a6d9-9a0a06d5653f" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_ca093ba3-a318-4926-87e4-1756b29ed646" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_TenaskaPPAMember_20c82316-def3-426c-9158-d6e75c025fe3" xlink:href="ale-20210930.xsd#ale_TenaskaPPAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_ca093ba3-a318-4926-87e4-1756b29ed646" xlink:to="loc_ale_TenaskaPPAMember_20c82316-def3-426c-9158-d6e75c025fe3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_a6961e05-94e5-4214-a73a-378f2d04e1a4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_7effefea-f6dd-4b59-ac89-2db4ac7332ca" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_a6961e05-94e5-4214-a73a-378f2d04e1a4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_a6961e05-94e5-4214-a73a-378f2d04e1a4_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_a6961e05-94e5-4214-a73a-378f2d04e1a4" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_a6961e05-94e5-4214-a73a-378f2d04e1a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_8c748a4b-a9ba-4954-9fca-3f6c333a70c4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_a6961e05-94e5-4214-a73a-378f2d04e1a4" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_8c748a4b-a9ba-4954-9fca-3f6c333a70c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_Nobles2Member_4d262caf-97cf-4891-a5b2-606e852d57c4" xlink:href="ale-20210930.xsd#ale_Nobles2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8c748a4b-a9ba-4954-9fca-3f6c333a70c4" xlink:to="loc_ale_Nobles2Member_4d262caf-97cf-4891-a5b2-606e852d57c4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/FairValueRecurringFairValueMeasuresDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#FairValueRecurringFairValueMeasuresDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/FairValueRecurringFairValueMeasuresDetails" xlink:type="extended" id="i29ecbf752f844d69a513c81b5d3053ff_FairValueRecurringFairValueMeasuresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01e9b4a9-9b84-4316-b476-37fa30b7b9a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01e9b4a9-9b84-4316-b476-37fa30b7b9a6" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsAbstract_ae673b42-9778-46aa-b177-18b1a851eba3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:to="loc_us-gaap_InvestmentsAbstract_ae673b42-9778-46aa-b177-18b1a851eba3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFVNINoncurrent_a6827500-f089-4e80-96fc-91851a3d24c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesFVNINoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsAbstract_ae673b42-9778-46aa-b177-18b1a851eba3" xlink:to="loc_us-gaap_EquitySecuritiesFVNINoncurrent_a6827500-f089-4e80-96fc-91851a3d24c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_d2413db7-14a4-48fc-8696-3df083775295" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsAbstract_ae673b42-9778-46aa-b177-18b1a851eba3" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_d2413db7-14a4-48fc-8696-3df083775295" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherRestrictedAssetsNoncurrent_21989cfd-a3e2-4e3f-b8f6-c90bb6934107" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherRestrictedAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsAbstract_ae673b42-9778-46aa-b177-18b1a851eba3" xlink:to="loc_us-gaap_OtherRestrictedAssetsNoncurrent_21989cfd-a3e2-4e3f-b8f6-c90bb6934107" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_cadba750-9290-4c4b-b6a5-e1ee29483653" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_cadba750-9290-4c4b-b6a5-e1ee29483653" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_1fece6c7-3314-4e08-bc34-43d6f6f0dfd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_1fece6c7-3314-4e08-bc34-43d6f6f0dfd1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AvailableforsaleSecuritiesDebtMaturitiesAfterOneYearThroughThreeYearsFairValue_30c97971-600b-4e4f-916c-ebd1d1067ed8" xlink:href="ale-20210930.xsd#ale_AvailableforsaleSecuritiesDebtMaturitiesAfterOneYearThroughThreeYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:to="loc_ale_AvailableforsaleSecuritiesDebtMaturitiesAfterOneYearThroughThreeYearsFairValue_30c97971-600b-4e4f-916c-ebd1d1067ed8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AvailableforsaleSecuritiesDebtMaturitiesAfterThreeYearsThroughFiveYearsFairValue_4e9fcabe-b11f-474a-a13b-f95a9ed52df0" xlink:href="ale-20210930.xsd#ale_AvailableforsaleSecuritiesDebtMaturitiesAfterThreeYearsThroughFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:to="loc_ale_AvailableforsaleSecuritiesDebtMaturitiesAfterThreeYearsThroughFiveYearsFairValue_4e9fcabe-b11f-474a-a13b-f95a9ed52df0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AvailableforsaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue_9fbc117f-62f2-4a4a-871d-b6b1e7a65312" xlink:href="ale-20210930.xsd#ale_AvailableforsaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_815114da-f9fc-4932-9fe9-b6e6d7c903da" xlink:to="loc_ale_AvailableforsaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue_9fbc117f-62f2-4a4a-871d-b6b1e7a65312" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_d117ea5a-c3de-4a4d-82bd-822d03586557" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01e9b4a9-9b84-4316-b476-37fa30b7b9a6" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_d117ea5a-c3de-4a4d-82bd-822d03586557" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DeferredCompensationFairValueDisclosure_580ef768-f7bd-43e8-918a-a64fa7e7968d" xlink:href="ale-20210930.xsd#ale_DeferredCompensationFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_d117ea5a-c3de-4a4d-82bd-822d03586557" xlink:to="loc_ale_DeferredCompensationFairValueDisclosure_580ef768-f7bd-43e8-918a-a64fa7e7968d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_c1e95583-ecc2-4ce8-8bf4-f9e85831969d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_d117ea5a-c3de-4a4d-82bd-822d03586557" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_c1e95583-ecc2-4ce8-8bf4-f9e85831969d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetAssetLiability_276105fe-e3c4-466f-ab2f-b4f0deadad7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueNetAssetLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01e9b4a9-9b84-4316-b476-37fa30b7b9a6" xlink:to="loc_us-gaap_FairValueNetAssetLiability_276105fe-e3c4-466f-ab2f-b4f0deadad7d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b86ad213-2b96-4bf2-b3f9-02eee2f8fe50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01e9b4a9-9b84-4316-b476-37fa30b7b9a6" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b86ad213-2b96-4bf2-b3f9-02eee2f8fe50" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_35bfe0be-28f3-4d73-81b8-5cce9cc21a34" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b86ad213-2b96-4bf2-b3f9-02eee2f8fe50" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_35bfe0be-28f3-4d73-81b8-5cce9cc21a34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_35bfe0be-28f3-4d73-81b8-5cce9cc21a34_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_35bfe0be-28f3-4d73-81b8-5cce9cc21a34" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_35bfe0be-28f3-4d73-81b8-5cce9cc21a34_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_1c353512-9a3e-4c4e-8b4a-5d0473c0b416" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_35bfe0be-28f3-4d73-81b8-5cce9cc21a34" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_1c353512-9a3e-4c4e-8b4a-5d0473c0b416" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_56a6349f-fa98-4c6d-a1f8-6db79ea84fc0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_1c353512-9a3e-4c4e-8b4a-5d0473c0b416" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_56a6349f-fa98-4c6d-a1f8-6db79ea84fc0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b00af4f4-19f5-43d9-9afe-16537c60adfd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b86ad213-2b96-4bf2-b3f9-02eee2f8fe50" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b00af4f4-19f5-43d9-9afe-16537c60adfd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b00af4f4-19f5-43d9-9afe-16537c60adfd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b00af4f4-19f5-43d9-9afe-16537c60adfd" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b00af4f4-19f5-43d9-9afe-16537c60adfd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1eefe0ac-9aea-4e14-a9fe-6d6d5d472358" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b00af4f4-19f5-43d9-9afe-16537c60adfd" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1eefe0ac-9aea-4e14-a9fe-6d6d5d472358" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_e3a35560-37ac-4cd4-b380-65ab58512236" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1eefe0ac-9aea-4e14-a9fe-6d6d5d472358" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_e3a35560-37ac-4cd4-b380-65ab58512236" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_c35b1f5d-045f-4ebd-bfe3-594955d62b59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1eefe0ac-9aea-4e14-a9fe-6d6d5d472358" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_c35b1f5d-045f-4ebd-bfe3-594955d62b59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_85e015a4-bc43-468f-a011-b69cb782740c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1eefe0ac-9aea-4e14-a9fe-6d6d5d472358" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_85e015a4-bc43-468f-a011-b69cb782740c" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/FairValueFairValueofFinancialInstrumentsandAssetsMeasuredonaNonrecurringBasisDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#FairValueFairValueofFinancialInstrumentsandAssetsMeasuredonaNonrecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/FairValueFairValueofFinancialInstrumentsandAssetsMeasuredonaNonrecurringBasisDetails" xlink:type="extended" id="i6465514263574ccbab2513ed3fffb17a_FairValueFairValueofFinancialInstrumentsandAssetsMeasuredonaNonrecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5b7af9db-698d-403d-b155-b4d9c26f4686" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_7df9745c-4ef6-4a85-ac0b-61f199688b0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5b7af9db-698d-403d-b155-b4d9c26f4686" xlink:to="loc_us-gaap_LongTermDebt_7df9745c-4ef6-4a85-ac0b-61f199688b0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_1f69e1de-9abe-4564-bb3e-9e9e4dd2b9e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5b7af9db-698d-403d-b155-b4d9c26f4686" xlink:to="loc_us-gaap_LongTermDebtFairValue_1f69e1de-9abe-4564-bb3e-9e9e4dd2b9e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_f4426b0b-f0a5-424f-9983-d16a0a841efd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5b7af9db-698d-403d-b155-b4d9c26f4686" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_f4426b0b-f0a5-424f-9983-d16a0a841efd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_72051002-f73b-4aa9-b01f-f2ccf36163a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_f4426b0b-f0a5-424f-9983-d16a0a841efd" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_72051002-f73b-4aa9-b01f-f2ccf36163a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_72051002-f73b-4aa9-b01f-f2ccf36163a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_72051002-f73b-4aa9-b01f-f2ccf36163a7" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_72051002-f73b-4aa9-b01f-f2ccf36163a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7f45d695-135f-4437-8d37-2a422805a26c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_72051002-f73b-4aa9-b01f-f2ccf36163a7" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7f45d695-135f-4437-8d37-2a422805a26c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_2169b27a-8622-43ae-b04f-603f5f4576d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7f45d695-135f-4437-8d37-2a422805a26c" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_2169b27a-8622-43ae-b04f-603f5f4576d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_449c375a-862c-4931-b331-8d1a02a7f498" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_f4426b0b-f0a5-424f-9983-d16a0a841efd" xlink:to="loc_srt_ConsolidatedEntitiesAxis_449c375a-862c-4931-b331-8d1a02a7f498" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_449c375a-862c-4931-b331-8d1a02a7f498_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_449c375a-862c-4931-b331-8d1a02a7f498" xlink:to="loc_srt_ConsolidatedEntitiesDomain_449c375a-862c-4931-b331-8d1a02a7f498_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_812b5d91-340b-4095-9781-011dc66e5ae2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_449c375a-862c-4931-b331-8d1a02a7f498" xlink:to="loc_srt_ConsolidatedEntitiesDomain_812b5d91-340b-4095-9781-011dc66e5ae2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETECleanEnergyMember_dae2d22f-a94d-4abb-9839-8ce527399e4f" xlink:href="ale-20210930.xsd#ale_ALLETECleanEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_812b5d91-340b-4095-9781-011dc66e5ae2" xlink:to="loc_ale_ALLETECleanEnergyMember_dae2d22f-a94d-4abb-9839-8ce527399e4f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/ShortTermandLongTermDebtDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#ShortTermandLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/ShortTermandLongTermDebtDetails" xlink:type="extended" id="i48d0d82440fb42de862da744a85bea94_ShortTermandLongTermDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DebtCurrentGross_810d1e9e-4e40-4586-8510-bfba56f9e5b1" xlink:href="ale-20210930.xsd#ale_DebtCurrentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_DebtCurrentGross_810d1e9e-4e40-4586-8510-bfba56f9e5b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_UnamortizedDebtIssuanceExpenseDebtCurrent_83edc169-1568-4c27-9071-ead5aca56096" xlink:href="ale-20210930.xsd#ale_UnamortizedDebtIssuanceExpenseDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_UnamortizedDebtIssuanceExpenseDebtCurrent_83edc169-1568-4c27-9071-ead5aca56096" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtCurrent_fc2b5a23-cb92-42fb-941b-de502dda2b60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtCurrent_fc2b5a23-cb92-42fb-941b-de502dda2b60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_37279d10-1d75-4161-9b5c-7ad8fdec3f38" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_37279d10-1d75-4161-9b5c-7ad8fdec3f38" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_UnamortizedDebtIssuanceExpenseLongTermDebtExcludingCurrentMaturities_540844b9-d055-40e3-a95a-bc99425def57" xlink:href="ale-20210930.xsd#ale_UnamortizedDebtIssuanceExpenseLongTermDebtExcludingCurrentMaturities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_UnamortizedDebtIssuanceExpenseLongTermDebtExcludingCurrentMaturities_540844b9-d055-40e3-a95a-bc99425def57" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_4ec02ae5-e8c7-4104-adcf-9d3cae70e4d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_4ec02ae5-e8c7-4104-adcf-9d3cae70e4d3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DebtLongTermandShortTermCombinedAmountGross_265f95c9-34e8-4bb3-ab34-b12cc0b31134" xlink:href="ale-20210930.xsd#ale_DebtLongTermandShortTermCombinedAmountGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_DebtLongTermandShortTermCombinedAmountGross_265f95c9-34e8-4bb3-ab34-b12cc0b31134" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnamortizedDebtIssuanceExpense_50e57a75-a73f-4089-9924-1e95a4a5f3be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnamortizedDebtIssuanceExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_UnamortizedDebtIssuanceExpense_50e57a75-a73f-4089-9924-1e95a4a5f3be" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_5440455d-e3e9-47e7-bb62-597bdf9c2204" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_5440455d-e3e9-47e7-bb62-597bdf9c2204" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_e10b3f93-d0ac-413d-b8da-efbfff56a0bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_e10b3f93-d0ac-413d-b8da-efbfff56a0bb" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LinesOfCreditCurrent_c3b18726-1c95-4bea-b2ac-deaed31512ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LinesOfCreditCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_LinesOfCreditCurrent_c3b18726-1c95-4bea-b2ac-deaed31512ba" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_UnsecuredTermLoanAmount_277fbe43-7e19-43c9-a173-4ff613b17eac" xlink:href="ale-20210930.xsd#ale_UnsecuredTermLoanAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_UnsecuredTermLoanAmount_277fbe43-7e19-43c9-a173-4ff613b17eac" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_a78e6fb3-e474-48b7-a021-f822c5e9854e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_a78e6fb3-e474-48b7-a021-f822c5e9854e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_dfa46453-39fe-4944-a38a-1cbb2b36b71f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_dfa46453-39fe-4944-a38a-1cbb2b36b71f" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfFirstMortgageBond_52f8b702-1a79-4241-9490-c12fb532c988" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfFirstMortgageBond"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfFirstMortgageBond_52f8b702-1a79-4241-9490-c12fb532c988" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_81f85db4-178d-4cd0-ad36-5384ea85bf24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_81f85db4-178d-4cd0-ad36-5384ea85bf24" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DebtDrawnThroughAccordionFeature_8400e016-644e-40dc-bf4e-127f3a160705" xlink:href="ale-20210930.xsd#ale_DebtDrawnThroughAccordionFeature"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_DebtDrawnThroughAccordionFeature_8400e016-644e-40dc-bf4e-127f3a160705" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_UnsecuredDebtTotalDrawnOnLoan_9b4c2f33-44a3-4edf-9903-bf865210b9c3" xlink:href="ale-20210930.xsd#ale_UnsecuredDebtTotalDrawnOnLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_ale_UnsecuredDebtTotalDrawnOnLoan_9b4c2f33-44a3-4edf-9903-bf865210b9c3" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_da65eb84-f8a0-407e-8135-90e14174f9dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cbfae776-1620-4269-b02c-14e0b9bb118a" xlink:to="loc_us-gaap_DebtInstrumentTable_da65eb84-f8a0-407e-8135-90e14174f9dd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_97e388d8-600b-4e60-86de-e965b5716187" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_da65eb84-f8a0-407e-8135-90e14174f9dd" xlink:to="loc_us-gaap_DebtInstrumentAxis_97e388d8-600b-4e60-86de-e965b5716187" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_97e388d8-600b-4e60-86de-e965b5716187_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_97e388d8-600b-4e60-86de-e965b5716187" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_97e388d8-600b-4e60-86de-e965b5716187_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1ff3ffef-7021-4577-9003-c80100fd5a39" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_97e388d8-600b-4e60-86de-e965b5716187" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1ff3ffef-7021-4577-9003-c80100fd5a39" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_UnsecuredTermLoanDueIn2022Member_db6850f9-68bf-4b33-a53c-34edb14fa67c" xlink:href="ale-20210930.xsd#ale_UnsecuredTermLoanDueIn2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1ff3ffef-7021-4577-9003-c80100fd5a39" xlink:to="loc_ale_UnsecuredTermLoanDueIn2022Member_db6850f9-68bf-4b33-a53c-34edb14fa67c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETEBonds279DueSeptember2031Member_66f6e5c5-e0b0-4e50-a484-70f99c33a794" xlink:href="ale-20210930.xsd#ale_ALLETEBonds279DueSeptember2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1ff3ffef-7021-4577-9003-c80100fd5a39" xlink:to="loc_ale_ALLETEBonds279DueSeptember2031Member_66f6e5c5-e0b0-4e50-a484-70f99c33a794" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_c6ceb5d6-c73a-4b30-b73a-9f0ce1931735" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1ff3ffef-7021-4577-9003-c80100fd5a39" xlink:to="loc_us-gaap_LineOfCreditMember_c6ceb5d6-c73a-4b30-b73a-9f0ce1931735" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/ShortTermandLongTermDebtFinancialCovenantsDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#ShortTermandLongTermDebtFinancialCovenantsDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/ShortTermandLongTermDebtFinancialCovenantsDetails" xlink:type="extended" id="i6ce6a44f0beb44e191bb6c0f79ab7223_ShortTermandLongTermDebtFinancialCovenantsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_56ff89c9-4c58-4bb4-b105-2c43bff3da09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DebtInstrumentRequiredIndebtednessToTotalCapitalRatio_af8902c1-90f2-4c3f-814e-955b26f3a1fc" xlink:href="ale-20210930.xsd#ale_DebtInstrumentRequiredIndebtednessToTotalCapitalRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_56ff89c9-4c58-4bb4-b105-2c43bff3da09" xlink:to="loc_ale_DebtInstrumentRequiredIndebtednessToTotalCapitalRatio_af8902c1-90f2-4c3f-814e-955b26f3a1fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_DebtInstrumentActualIndebtednessToTotalCapitalRatio_72fcfdb4-6bff-451f-b0be-43258e8f9764" xlink:href="ale-20210930.xsd#ale_DebtInstrumentActualIndebtednessToTotalCapitalRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_56ff89c9-4c58-4bb4-b105-2c43bff3da09" xlink:to="loc_ale_DebtInstrumentActualIndebtednessToTotalCapitalRatio_72fcfdb4-6bff-451f-b0be-43258e8f9764" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_3a947a44-df0c-4bad-8b48-e721f1ca5ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_56ff89c9-4c58-4bb4-b105-2c43bff3da09" xlink:to="loc_us-gaap_DebtInstrumentTable_3a947a44-df0c-4bad-8b48-e721f1ca5ec0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1b2b88a8-2206-4558-889a-5302b7c5c538" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3a947a44-df0c-4bad-8b48-e721f1ca5ec0" xlink:to="loc_srt_RangeAxis_1b2b88a8-2206-4558-889a-5302b7c5c538" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1b2b88a8-2206-4558-889a-5302b7c5c538_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1b2b88a8-2206-4558-889a-5302b7c5c538" xlink:to="loc_srt_RangeMember_1b2b88a8-2206-4558-889a-5302b7c5c538_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_acbe14fa-3e71-4dcf-9244-9e7cf17de397" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1b2b88a8-2206-4558-889a-5302b7c5c538" xlink:to="loc_srt_RangeMember_acbe14fa-3e71-4dcf-9244-9e7cf17de397" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_57ec19a1-a2db-4f2d-ab10-025ea89acf59" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_acbe14fa-3e71-4dcf-9244-9e7cf17de397" xlink:to="loc_srt_MaximumMember_57ec19a1-a2db-4f2d-ab10-025ea89acf59" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesPowerPurchaseAgreementsDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#CommitmentsGuaranteesandContingenciesPowerPurchaseAgreementsDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesPowerPurchaseAgreementsDetails" xlink:type="extended" id="i6a58fc5f7edd40e1a1eaeae86d642db9_CommitmentsGuaranteesandContingenciesPowerPurchaseAgreementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems_e64166cb-1ffd-4a2c-8b7e-85c465047d0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAmountOfLongTermDebtOrLeaseObligationOutstanding_1cdaa42d-26db-4bf3-8107-c3c730149837" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAmountOfLongTermDebtOrLeaseObligationOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems_e64166cb-1ffd-4a2c-8b7e-85c465047d0b" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAmountOfLongTermDebtOrLeaseObligationOutstanding_1cdaa42d-26db-4bf3-8107-c3c730149837" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilitiesOperatingExpensePurchasedPowerUnderLongTermContracts_8f0eba60-e7b9-451c-ac18-add9d53c29da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UtilitiesOperatingExpensePurchasedPowerUnderLongTermContracts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems_e64166cb-1ffd-4a2c-8b7e-85c465047d0b" xlink:to="loc_us-gaap_UtilitiesOperatingExpensePurchasedPowerUnderLongTermContracts_8f0eba60-e7b9-451c-ac18-add9d53c29da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased_c8c810b4-1e75-4216-919a-497908bcb77e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems_e64166cb-1ffd-4a2c-8b7e-85c465047d0b" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchased_c8c810b4-1e75-4216-919a-497908bcb77e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerInterestIncludedInContractCharges_b4f3fa15-60b5-4ad5-9105-cc3191b8118e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerInterestIncludedInContractCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems_e64166cb-1ffd-4a2c-8b7e-85c465047d0b" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerInterestIncludedInContractCharges_b4f3fa15-60b5-4ad5-9105-cc3191b8118e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractsForPurchaseOfElectricPowerTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerLineItems_e64166cb-1ffd-4a2c-8b7e-85c465047d0b" xlink:to="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_96bce075-df21-42e8-a341-5208271a5278" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:to="loc_srt_CounterpartyNameAxis_96bce075-df21-42e8-a341-5208271a5278" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_96bce075-df21-42e8-a341-5208271a5278_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_96bce075-df21-42e8-a341-5208271a5278" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_96bce075-df21-42e8-a341-5208271a5278_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4b954b84-6c26-435b-8f54-5993cad93065" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_96bce075-df21-42e8-a341-5208271a5278" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4b954b84-6c26-435b-8f54-5993cad93065" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SquareButteMember_3fb5d21d-e183-42f3-9ec5-7e4499439f3b" xlink:href="ale-20210930.xsd#ale_SquareButteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4b954b84-6c26-435b-8f54-5993cad93065" xlink:to="loc_ale_SquareButteMember_3fb5d21d-e183-42f3-9ec5-7e4499439f3b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnkotaPowerMember_523650a2-3f70-4e1c-81f4-c8000bbfc70f" xlink:href="ale-20210930.xsd#ale_MinnkotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4b954b84-6c26-435b-8f54-5993cad93065" xlink:to="loc_ale_MinnkotaPowerMember_523650a2-3f70-4e1c-81f4-c8000bbfc70f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_f8818a42-887e-485d-a2d6-e07d6ef25bef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_f8818a42-887e-485d-a2d6-e07d6ef25bef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_f8818a42-887e-485d-a2d6-e07d6ef25bef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_f8818a42-887e-485d-a2d6-e07d6ef25bef" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_f8818a42-887e-485d-a2d6-e07d6ef25bef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_abc69f33-98bb-4fba-a4ef-b665d2694fd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_f8818a42-887e-485d-a2d6-e07d6ef25bef" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_abc69f33-98bb-4fba-a4ef-b665d2694fd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SquareButtePpaMember_107790b3-771c-4192-8de2-470eb129834e" xlink:href="ale-20210930.xsd#ale_SquareButtePpaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_abc69f33-98bb-4fba-a4ef-b665d2694fd5" xlink:to="loc_ale_SquareButtePpaMember_107790b3-771c-4192-8de2-470eb129834e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_3dbd5419-d256-4bfb-a84a-8d5dccf2d43e" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:to="loc_dei_LegalEntityAxis_3dbd5419-d256-4bfb-a84a-8d5dccf2d43e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_3dbd5419-d256-4bfb-a84a-8d5dccf2d43e_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_3dbd5419-d256-4bfb-a84a-8d5dccf2d43e" xlink:to="loc_dei_EntityDomain_3dbd5419-d256-4bfb-a84a-8d5dccf2d43e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_363c6bb1-32ae-4137-9a9c-8c893c62fb35" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_3dbd5419-d256-4bfb-a84a-8d5dccf2d43e" xlink:to="loc_dei_EntityDomain_363c6bb1-32ae-4137-9a9c-8c893c62fb35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_a3fdf5db-c2b9-46b5-9fec-b878a8dc715e" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_363c6bb1-32ae-4137-9a9c-8c893c62fb35" xlink:to="loc_ale_MinnesotaPowerMember_a3fdf5db-c2b9-46b5-9fec-b878a8dc715e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityAxisAxis_2918585d-c06d-4ec5-a835-723d7e21f749" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityAxisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:to="loc_ale_GeneratingFacilityAxisAxis_2918585d-c06d-4ec5-a835-723d7e21f749" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_2918585d-c06d-4ec5-a835-723d7e21f749_default" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GeneratingFacilityAxisAxis_2918585d-c06d-4ec5-a835-723d7e21f749" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_2918585d-c06d-4ec5-a835-723d7e21f749_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GeneratingFacilityUnitNameDomain_6254b3ee-6e67-4f97-9b08-b7fa82002ce6" xlink:href="ale-20210930.xsd#ale_GeneratingFacilityUnitNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GeneratingFacilityAxisAxis_2918585d-c06d-4ec5-a835-723d7e21f749" xlink:to="loc_ale_GeneratingFacilityUnitNameDomain_6254b3ee-6e67-4f97-9b08-b7fa82002ce6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SquareButteCoalFiredUnitMember_0596358b-6fb2-470f-b106-bf234a5ebbb4" xlink:href="ale-20210930.xsd#ale_SquareButteCoalFiredUnitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GeneratingFacilityUnitNameDomain_6254b3ee-6e67-4f97-9b08-b7fa82002ce6" xlink:to="loc_ale_SquareButteCoalFiredUnitMember_0596358b-6fb2-470f-b106-bf234a5ebbb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_LongtermContractsforSaleofElectricPowerAxis_9013a154-2d93-4300-8d0c-ce5701c77af8" xlink:href="ale-20210930.xsd#ale_LongtermContractsforSaleofElectricPowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LongTermContractsForPurchaseOfElectricPowerTable_466cafc8-8aa3-4340-9a21-29c7e1abc40d" xlink:to="loc_ale_LongtermContractsforSaleofElectricPowerAxis_9013a154-2d93-4300-8d0c-ce5701c77af8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_LongtermContractsforSaleofElectricPowerDomain_9013a154-2d93-4300-8d0c-ce5701c77af8_default" xlink:href="ale-20210930.xsd#ale_LongtermContractsforSaleofElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_LongtermContractsforSaleofElectricPowerAxis_9013a154-2d93-4300-8d0c-ce5701c77af8" xlink:to="loc_ale_LongtermContractsforSaleofElectricPowerDomain_9013a154-2d93-4300-8d0c-ce5701c77af8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_LongtermContractsforSaleofElectricPowerDomain_4112d027-744f-47ac-a305-d136cc31e6d5" xlink:href="ale-20210930.xsd#ale_LongtermContractsforSaleofElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_LongtermContractsforSaleofElectricPowerAxis_9013a154-2d93-4300-8d0c-ce5701c77af8" xlink:to="loc_ale_LongtermContractsforSaleofElectricPowerDomain_4112d027-744f-47ac-a305-d136cc31e6d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnkotaSalesAgreementMember_5e5d70ae-978b-4cc3-9c44-eb55bccebb00" xlink:href="ale-20210930.xsd#ale_MinnkotaSalesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_LongtermContractsforSaleofElectricPowerDomain_4112d027-744f-47ac-a305-d136cc31e6d5" xlink:to="loc_ale_MinnkotaSalesAgreementMember_5e5d70ae-978b-4cc3-9c44-eb55bccebb00" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesCoalRailandShippingContractsDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#CommitmentsGuaranteesandContingenciesCoalRailandShippingContractsDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesCoalRailandShippingContractsDetails" xlink:type="extended" id="ib34b28bb4ae14593ae527625a96433bf_CommitmentsGuaranteesandContingenciesCoalRailandShippingContractsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_db908262-57a2-4331-979b-53b9681292e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a6bf2435-d6cc-41f9-9c02-d183722743f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_db908262-57a2-4331-979b-53b9681292e6" xlink:to="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a6bf2435-d6cc-41f9-9c02-d183722743f5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis_e19f1347-b9d5-4632-a6c7-c8dff1dd8283" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a6bf2435-d6cc-41f9-9c02-d183722743f5" xlink:to="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis_e19f1347-b9d5-4632-a6c7-c8dff1dd8283" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnconditionalPurchaseObligationCategoryOfGoodsOrServicesAcquiredDomain_e19f1347-b9d5-4632-a6c7-c8dff1dd8283_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnconditionalPurchaseObligationCategoryOfGoodsOrServicesAcquiredDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis_e19f1347-b9d5-4632-a6c7-c8dff1dd8283" xlink:to="loc_us-gaap_UnconditionalPurchaseObligationCategoryOfGoodsOrServicesAcquiredDomain_e19f1347-b9d5-4632-a6c7-c8dff1dd8283_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnconditionalPurchaseObligationCategoryOfGoodsOrServicesAcquiredDomain_600661c5-aa4e-4eb2-8f6e-46a43bba7fa6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnconditionalPurchaseObligationCategoryOfGoodsOrServicesAcquiredDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis_e19f1347-b9d5-4632-a6c7-c8dff1dd8283" xlink:to="loc_us-gaap_UnconditionalPurchaseObligationCategoryOfGoodsOrServicesAcquiredDomain_600661c5-aa4e-4eb2-8f6e-46a43bba7fa6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_7d195b29-490c-4743-b120-56dac1b19d01" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a6bf2435-d6cc-41f9-9c02-d183722743f5" xlink:to="loc_dei_LegalEntityAxis_7d195b29-490c-4743-b120-56dac1b19d01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_7d195b29-490c-4743-b120-56dac1b19d01_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_7d195b29-490c-4743-b120-56dac1b19d01" xlink:to="loc_dei_EntityDomain_7d195b29-490c-4743-b120-56dac1b19d01_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_74f1c3ae-6f9d-40ee-b7e7-2585cc179491" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_7d195b29-490c-4743-b120-56dac1b19d01" xlink:to="loc_dei_EntityDomain_74f1c3ae-6f9d-40ee-b7e7-2585cc179491" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_8102fd0b-c09e-4507-a497-944dd237c991" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_74f1c3ae-6f9d-40ee-b7e7-2585cc179491" xlink:to="loc_ale_MinnesotaPowerMember_8102fd0b-c09e-4507-a497-944dd237c991" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesEnvironmentalMattersDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#CommitmentsGuaranteesandContingenciesEnvironmentalMattersDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesEnvironmentalMattersDetails" xlink:type="extended" id="i4eb0d4674eca48569161dd2f4ddc58d8_CommitmentsGuaranteesandContingenciesEnvironmentalMattersDetails">
    <link:loc xlink:type="locator" xlink:label="loc_ale_EnvironmentalMattersLineItems_39165d2b-1a3a-4b26-82b4-854519d0b6bd" xlink:href="ale-20210930.xsd#ale_EnvironmentalMattersLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate_c3aec58e-59ed-457b-9527-ba47d618842e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_EnvironmentalMattersLineItems_39165d2b-1a3a-4b26-82b4-854519d0b6bd" xlink:to="loc_us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate_c3aec58e-59ed-457b-9527-ba47d618842e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ExpectedPeriodforCostsofCompliance_07a037d0-6f22-4223-abd2-86b7f724407e" xlink:href="ale-20210930.xsd#ale_ExpectedPeriodforCostsofCompliance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_EnvironmentalMattersLineItems_39165d2b-1a3a-4b26-82b4-854519d0b6bd" xlink:to="loc_ale_ExpectedPeriodforCostsofCompliance_07a037d0-6f22-4223-abd2-86b7f724407e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingencies_e2d04e94-95ea-4d22-9342-e3070fc1270b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_EnvironmentalMattersLineItems_39165d2b-1a3a-4b26-82b4-854519d0b6bd" xlink:to="loc_us-gaap_AccrualForEnvironmentalLossContingencies_e2d04e94-95ea-4d22-9342-e3070fc1270b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_EnvironmentalMattersTable_3650e01e-8839-44e4-be44-ad15ae0ed386" xlink:href="ale-20210930.xsd#ale_EnvironmentalMattersTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ale_EnvironmentalMattersLineItems_39165d2b-1a3a-4b26-82b4-854519d0b6bd" xlink:to="loc_ale_EnvironmentalMattersTable_3650e01e-8839-44e4-be44-ad15ae0ed386" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRemediationContingencyAxis_9960be58-b665-48ce-8103-ecb35070f830" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EnvironmentalRemediationContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_EnvironmentalMattersTable_3650e01e-8839-44e4-be44-ad15ae0ed386" xlink:to="loc_us-gaap_EnvironmentalRemediationContingencyAxis_9960be58-b665-48ce-8103-ecb35070f830" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRemediationContingencyDomain_9960be58-b665-48ce-8103-ecb35070f830_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EnvironmentalRemediationContingencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EnvironmentalRemediationContingencyAxis_9960be58-b665-48ce-8103-ecb35070f830" xlink:to="loc_us-gaap_EnvironmentalRemediationContingencyDomain_9960be58-b665-48ce-8103-ecb35070f830_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRemediationContingencyDomain_b5fc9e67-0407-4355-9a2e-45a7150de46a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EnvironmentalRemediationContingencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EnvironmentalRemediationContingencyAxis_9960be58-b665-48ce-8103-ecb35070f830" xlink:to="loc_us-gaap_EnvironmentalRemediationContingencyDomain_b5fc9e67-0407-4355-9a2e-45a7150de46a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CoalCombustionResidualsMember_7c93dd0a-7df1-4445-9f85-c1adb84c9429" xlink:href="ale-20210930.xsd#ale_CoalCombustionResidualsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EnvironmentalRemediationContingencyDomain_b5fc9e67-0407-4355-9a2e-45a7150de46a" xlink:to="loc_ale_CoalCombustionResidualsMember_7c93dd0a-7df1-4445-9f85-c1adb84c9429" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ManufacturedGasPlantMember_5c66c49e-e613-472f-ae83-4fa04129d062" xlink:href="ale-20210930.xsd#ale_ManufacturedGasPlantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EnvironmentalRemediationContingencyDomain_b5fc9e67-0407-4355-9a2e-45a7150de46a" xlink:to="loc_ale_ManufacturedGasPlantMember_5c66c49e-e613-472f-ae83-4fa04129d062" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_b55aa3e8-1c88-48a7-bf95-8e8d8f067b94" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_EnvironmentalMattersTable_3650e01e-8839-44e4-be44-ad15ae0ed386" xlink:to="loc_srt_RangeAxis_b55aa3e8-1c88-48a7-bf95-8e8d8f067b94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b55aa3e8-1c88-48a7-bf95-8e8d8f067b94_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_b55aa3e8-1c88-48a7-bf95-8e8d8f067b94" xlink:to="loc_srt_RangeMember_b55aa3e8-1c88-48a7-bf95-8e8d8f067b94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e63caae6-dabe-401c-a4a1-88e9757b4d38" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_b55aa3e8-1c88-48a7-bf95-8e8d8f067b94" xlink:to="loc_srt_RangeMember_e63caae6-dabe-401c-a4a1-88e9757b4d38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_08862167-3bfa-43cf-abf9-d79636423cb2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e63caae6-dabe-401c-a4a1-88e9757b4d38" xlink:to="loc_srt_MinimumMember_08862167-3bfa-43cf-abf9-d79636423cb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_78c096b3-d161-48c5-8b55-602b716870a6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e63caae6-dabe-401c-a4a1-88e9757b4d38" xlink:to="loc_srt_MaximumMember_78c096b3-d161-48c5-8b55-602b716870a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_2d9d0e89-82c2-4938-8bb8-c3b331c15fa8" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_EnvironmentalMattersTable_3650e01e-8839-44e4-be44-ad15ae0ed386" xlink:to="loc_dei_LegalEntityAxis_2d9d0e89-82c2-4938-8bb8-c3b331c15fa8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_2d9d0e89-82c2-4938-8bb8-c3b331c15fa8_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_2d9d0e89-82c2-4938-8bb8-c3b331c15fa8" xlink:to="loc_dei_EntityDomain_2d9d0e89-82c2-4938-8bb8-c3b331c15fa8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_38d1bdd9-7798-48e7-b497-252dc178c2aa" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_2d9d0e89-82c2-4938-8bb8-c3b331c15fa8" xlink:to="loc_dei_EntityDomain_38d1bdd9-7798-48e7-b497-252dc178c2aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_001c85a5-6010-4124-88b5-8ca82ea195da" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_38d1bdd9-7798-48e7-b497-252dc178c2aa" xlink:to="loc_ale_MinnesotaPowerMember_001c85a5-6010-4124-88b5-8ca82ea195da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SWLPMember_64eaf2a2-d3e0-47a3-b978-84d631b7d693" xlink:href="ale-20210930.xsd#ale_SWLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_38d1bdd9-7798-48e7-b497-252dc178c2aa" xlink:to="loc_ale_SWLPMember_64eaf2a2-d3e0-47a3-b978-84d631b7d693" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_d94fbd7e-b429-4fcd-9de0-99c3eaabbffd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ale_EnvironmentalMattersTable_3650e01e-8839-44e4-be44-ad15ae0ed386" xlink:to="loc_srt_StatementGeographicalAxis_d94fbd7e-b429-4fcd-9de0-99c3eaabbffd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_d94fbd7e-b429-4fcd-9de0-99c3eaabbffd_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_d94fbd7e-b429-4fcd-9de0-99c3eaabbffd" xlink:to="loc_srt_SegmentGeographicalDomain_d94fbd7e-b429-4fcd-9de0-99c3eaabbffd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_0e1f3266-afb0-41ef-aec3-fec0ffdbf332" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_d94fbd7e-b429-4fcd-9de0-99c3eaabbffd" xlink:to="loc_srt_SegmentGeographicalDomain_0e1f3266-afb0-41ef-aec3-fec0ffdbf332" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SuperiorWIMember_bbd01874-2d7c-4b8c-9fae-7a2c8316713b" xlink:href="ale-20210930.xsd#ale_SuperiorWIMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_0e1f3266-afb0-41ef-aec3-fec0ffdbf332" xlink:to="loc_ale_SuperiorWIMember_bbd01874-2d7c-4b8c-9fae-7a2c8316713b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesOtherMattersDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#CommitmentsGuaranteesandContingenciesOtherMattersDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/CommitmentsGuaranteesandContingenciesOtherMattersDetails" xlink:type="extended" id="i6d5ee3f4162f40cb96d9509e68d4891b_CommitmentsGuaranteesandContingenciesOtherMattersDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GuarantorObligationsCollateralHeldDirectlyorbyThirdPartiesAmount_7374b45b-119e-496e-a3c8-e88a17a45db6" xlink:href="ale-20210930.xsd#ale_GuarantorObligationsCollateralHeldDirectlyorbyThirdPartiesAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:to="loc_ale_GuarantorObligationsCollateralHeldDirectlyorbyThirdPartiesAmount_7374b45b-119e-496e-a3c8-e88a17a45db6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_d2fa0e4f-fec2-4799-ae52-065667171b9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_d2fa0e4f-fec2-4799-ae52-065667171b9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CommunityDevelopmentDistrictObligationOwnershipOfPropertyBenefited_30387be4-ddd6-4c8e-86e0-b1bc5fbcf02e" xlink:href="ale-20210930.xsd#ale_CommunityDevelopmentDistrictObligationOwnershipOfPropertyBenefited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:to="loc_ale_CommunityDevelopmentDistrictObligationOwnershipOfPropertyBenefited_30387be4-ddd6-4c8e-86e0-b1bc5fbcf02e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CommunityDevelopmentDistrictObligationAnnualAssessment_b4179864-e1be-4bb3-95a0-f3ca052c3c35" xlink:href="ale-20210930.xsd#ale_CommunityDevelopmentDistrictObligationAnnualAssessment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:to="loc_ale_CommunityDevelopmentDistrictObligationAnnualAssessment_b4179864-e1be-4bb3-95a0-f3ca052c3c35" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_6bbef32e-05a7-469e-ae3a-f184ba11ecc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_6bbef32e-05a7-469e-ae3a-f184ba11ecc1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_d8a6a9d0-a2ae-4c24-8078-c71f0682b13e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_970f7db4-271f-4403-953d-bae22703776d" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_d8a6a9d0-a2ae-4c24-8078-c71f0682b13e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GuaranteeEntityandTypeAxis_d819198b-8b35-4fcb-9672-0db1054d1314" xlink:href="ale-20210930.xsd#ale_GuaranteeEntityandTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_d8a6a9d0-a2ae-4c24-8078-c71f0682b13e" xlink:to="loc_ale_GuaranteeEntityandTypeAxis_d819198b-8b35-4fcb-9672-0db1054d1314" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GuaranteeEntityandTypeDomain_d819198b-8b35-4fcb-9672-0db1054d1314_default" xlink:href="ale-20210930.xsd#ale_GuaranteeEntityandTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ale_GuaranteeEntityandTypeAxis_d819198b-8b35-4fcb-9672-0db1054d1314" xlink:to="loc_ale_GuaranteeEntityandTypeDomain_d819198b-8b35-4fcb-9672-0db1054d1314_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:href="ale-20210930.xsd#ale_GuaranteeEntityandTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ale_GuaranteeEntityandTypeAxis_d819198b-8b35-4fcb-9672-0db1054d1314" xlink:to="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RegulatedOperationsMember_e927ddc0-8320-4435-a492-5896427ae91b" xlink:href="ale-20210930.xsd#ale_RegulatedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_RegulatedOperationsMember_e927ddc0-8320-4435-a492-5896427ae91b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETECleanEnergyMember_93b4c4ea-25ef-4aa0-85f7-eb303ef82baf" xlink:href="ale-20210930.xsd#ale_ALLETECleanEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_ALLETECleanEnergyMember_93b4c4ea-25ef-4aa0-85f7-eb303ef82baf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_BniCoalReclamationLiabilityMember_6f70ffd7-6641-479f-8e04-1d7e8a4d894d" xlink:href="ale-20210930.xsd#ale_BniCoalReclamationLiabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_BniCoalReclamationLiabilityMember_6f70ffd7-6641-479f-8e04-1d7e8a4d894d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AlletePropertiesPerformanceAndMaintenanceObligationsMember_c46c7788-ce42-41ae-87e1-730d0a1d9050" xlink:href="ale-20210930.xsd#ale_AlletePropertiesPerformanceAndMaintenanceObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_AlletePropertiesPerformanceAndMaintenanceObligationsMember_c46c7788-ce42-41ae-87e1-730d0a1d9050" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_TownCenterCommunityDevelopmentDistrictMember_4b12ac6b-c60d-41a6-9fee-b9f2f5a94bbe" xlink:href="ale-20210930.xsd#ale_TownCenterCommunityDevelopmentDistrictMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_TownCenterCommunityDevelopmentDistrictMember_4b12ac6b-c60d-41a6-9fee-b9f2f5a94bbe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETESouthWindMember_615cfdea-43a8-43e7-ae4f-2adbb9ca39e1" xlink:href="ale-20210930.xsd#ale_ALLETESouthWindMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_ALLETESouthWindMember_615cfdea-43a8-43e7-ae4f-2adbb9ca39e1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MinnesotaPowerMember_76898211-c248-40c5-9c37-493d9b47ff93" xlink:href="ale-20210930.xsd#ale_MinnesotaPowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_MinnesotaPowerMember_76898211-c248-40c5-9c37-493d9b47ff93" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_AlleteIncMember_dda084bb-7d61-4a59-a311-abeb8743cfd6" xlink:href="ale-20210930.xsd#ale_AlleteIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_AlleteIncMember_dda084bb-7d61-4a59-a311-abeb8743cfd6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_SouthShoreEnergyMember_0010221b-ef58-4d9e-ae8e-d153f7855e0d" xlink:href="ale-20210930.xsd#ale_SouthShoreEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ale_GuaranteeEntityandTypeDomain_f4c3fec1-4070-4dd9-9e65-476a29a0c09e" xlink:to="loc_ale_SouthShoreEnergyMember_0010221b-ef58-4d9e-ae8e-d153f7855e0d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_692ffddb-ec68-4ad8-a3c6-1c134901a44e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_d8a6a9d0-a2ae-4c24-8078-c71f0682b13e" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_692ffddb-ec68-4ad8-a3c6-1c134901a44e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_692ffddb-ec68-4ad8-a3c6-1c134901a44e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_692ffddb-ec68-4ad8-a3c6-1c134901a44e" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_692ffddb-ec68-4ad8-a3c6-1c134901a44e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_92da93fa-d247-42b3-8c3e-b16c65a1ab7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_692ffddb-ec68-4ad8-a3c6-1c134901a44e" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_92da93fa-d247-42b3-8c3e-b16c65a1ab7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SuretyBondMember_b3735443-bad4-40ce-b176-18ff0186796d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SuretyBondMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_92da93fa-d247-42b3-8c3e-b16c65a1ab7c" xlink:to="loc_us-gaap_SuretyBondMember_b3735443-bad4-40ce-b176-18ff0186796d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_6d785fc7-3943-4b44-876c-b75f9684182f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_92da93fa-d247-42b3-8c3e-b16c65a1ab7c" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_6d785fc7-3943-4b44-876c-b75f9684182f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_18bba0bb-a382-4e60-a26c-9cf29d63c5fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_d8a6a9d0-a2ae-4c24-8078-c71f0682b13e" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_18bba0bb-a382-4e60-a26c-9cf29d63c5fd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_18bba0bb-a382-4e60-a26c-9cf29d63c5fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_18bba0bb-a382-4e60-a26c-9cf29d63c5fd" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_18bba0bb-a382-4e60-a26c-9cf29d63c5fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_b17ec9fe-9da6-420d-9e9a-7e88c58229f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_18bba0bb-a382-4e60-a26c-9cf29d63c5fd" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_b17ec9fe-9da6-420d-9e9a-7e88c58229f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETECleanEnergyOtherMember_d323b936-dbc0-4d5f-bc50-9e5414806ba2" xlink:href="ale-20210930.xsd#ale_ALLETECleanEnergyOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_b17ec9fe-9da6-420d-9e9a-7e88c58229f5" xlink:to="loc_ale_ALLETECleanEnergyOtherMember_d323b936-dbc0-4d5f-bc50-9e5414806ba2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_e9516b6d-08ea-4f6c-ae22-14b5dd72ca87" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_d8a6a9d0-a2ae-4c24-8078-c71f0682b13e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_e9516b6d-08ea-4f6c-ae22-14b5dd72ca87" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e9516b6d-08ea-4f6c-ae22-14b5dd72ca87_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_e9516b6d-08ea-4f6c-ae22-14b5dd72ca87" xlink:to="loc_us-gaap_SegmentDomain_e9516b6d-08ea-4f6c-ae22-14b5dd72ca87_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_22052d3c-3e99-4784-80bf-b1138456ba6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_e9516b6d-08ea-4f6c-ae22-14b5dd72ca87" xlink:to="loc_us-gaap_SegmentDomain_22052d3c-3e99-4784-80bf-b1138456ba6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETECleanEnergyMember_f35a1c06-3afe-4efe-b985-0c2c319a05fb" xlink:href="ale-20210930.xsd#ale_ALLETECleanEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_22052d3c-3e99-4784-80bf-b1138456ba6a" xlink:to="loc_ale_ALLETECleanEnergyMember_f35a1c06-3afe-4efe-b985-0c2c319a05fb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/PensionandOtherPostretirementBenefitPlansDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#PensionandOtherPostretirementBenefitPlansDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/PensionandOtherPostretirementBenefitPlansDetails" xlink:type="extended" id="i060cb4b77be7466bb04a609b3d3ca896_PensionandOtherPostretirementBenefitPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7a043bc1-123f-4c99-8bde-1e97ecdfe09a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7a043bc1-123f-4c99-8bde-1e97ecdfe09a" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_f292fa13-23a4-4587-9b89-8703b2264cfc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_f292fa13-23a4-4587-9b89-8703b2264cfc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_884ec7a4-c498-48cd-8cf5-e44577bc1145" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_884ec7a4-c498-48cd-8cf5-e44577bc1145" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_e52b0d9d-ad1e-4678-8cb4-aec74f233d1b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_e52b0d9d-ad1e-4678-8cb4-aec74f233d1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_a7b3dac8-bdf5-4517-8eaf-9035572b7508" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_a7b3dac8-bdf5-4517-8eaf-9035572b7508" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_ca168b62-6993-4e96-ae7e-8e8d8c1245a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_ca168b62-6993-4e96-ae7e-8e8d8c1245a0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_d64d94b6-7d84-4537-99d8-257837bb6a86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_5a84dce8-3e15-4bf9-bdaa-ecd573388cda" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_d64d94b6-7d84-4537-99d8-257837bb6a86" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_4b741d3c-e955-44db-8cb0-9dd429e046aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7a043bc1-123f-4c99-8bde-1e97ecdfe09a" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_4b741d3c-e955-44db-8cb0-9dd429e046aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_420c4d42-a595-410a-b353-eb3e55962400" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7a043bc1-123f-4c99-8bde-1e97ecdfe09a" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_420c4d42-a595-410a-b353-eb3e55962400" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_9ccc4b5e-baea-4990-993f-52f1cc00be0e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7a043bc1-123f-4c99-8bde-1e97ecdfe09a" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_9ccc4b5e-baea-4990-993f-52f1cc00be0e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_d527d2a8-3e06-4cca-84a2-03216cf8ca67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_9ccc4b5e-baea-4990-993f-52f1cc00be0e" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_d527d2a8-3e06-4cca-84a2-03216cf8ca67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_d527d2a8-3e06-4cca-84a2-03216cf8ca67_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_d527d2a8-3e06-4cca-84a2-03216cf8ca67" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_d527d2a8-3e06-4cca-84a2-03216cf8ca67_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_1e6a5a0e-bf2f-4b21-9e79-dbe60f44ba72" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_d527d2a8-3e06-4cca-84a2-03216cf8ca67" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_1e6a5a0e-bf2f-4b21-9e79-dbe60f44ba72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_141764ba-db82-4b3c-9fab-b027d4cb7c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_1e6a5a0e-bf2f-4b21-9e79-dbe60f44ba72" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_141764ba-db82-4b3c-9fab-b027d4cb7c3b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_796e5599-c4d9-4c3e-b1f7-5ea4eebee269" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_1e6a5a0e-bf2f-4b21-9e79-dbe60f44ba72" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_796e5599-c4d9-4c3e-b1f7-5ea4eebee269" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.allete.com/role/BusinessSegmentsDetails" xlink:type="simple" xlink:href="ale-20210930.xsd#BusinessSegmentsDetails"/>
  <link:definitionLink xlink:role="http://www.allete.com/role/BusinessSegmentsDetails" xlink:type="extended" id="i7680b0b3fae24ee2b21c4eb06bda50b0_BusinessSegmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_78f0b5f0-05ad-4ac9-88a7-55513d9c234a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_NumberOfReportableSegments_78f0b5f0-05ad-4ac9-88a7-55513d9c234a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_26fdfe65-7e94-406b-9cd4-a0be934d1967" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_NumberOfOperatingSegments_26fdfe65-7e94-406b-9cd4-a0be934d1967" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfLand_295c84a5-dc88-426e-8061-5fc993666d60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AreaOfLand"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_AreaOfLand_295c84a5-dc88-426e-8061-5fc993666d60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_320f3b1d-240e-4161-bbf2-6688508f080b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_320f3b1d-240e-4161-bbf2-6688508f080b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RevenueOtherThanCustomerRevenue_c3fcd784-c9ea-45ef-af95-06a75a7ce8f1" xlink:href="ale-20210930.xsd#ale_RevenueOtherThanCustomerRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_ale_RevenueOtherThanCustomerRevenue_c3fcd784-c9ea-45ef-af95-06a75a7ce8f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_5559e83a-6177-471f-9aa0-7793c713e90d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_Revenues_5559e83a-6177-471f-9aa0-7793c713e90d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_0ce39b1b-887c-4b87-8a8d-73caf697f618" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_NetIncomeLoss_0ce39b1b-887c-4b87-8a8d-73caf697f618" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_7504b228-a9c8-4985-8bd4-7da3bfe48e69" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_Assets_7504b228-a9c8-4985-8bd4-7da3bfe48e69" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_17af37a6-118c-4d0a-8447-8789f575bede" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8083a5d5-e269-4fb6-b1e3-eeb589995e9b" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_17af37a6-118c-4d0a-8447-8789f575bede" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_31e7b776-87d2-442f-978a-5de934ab0776" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_17af37a6-118c-4d0a-8447-8789f575bede" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_31e7b776-87d2-442f-978a-5de934ab0776" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_31e7b776-87d2-442f-978a-5de934ab0776_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_31e7b776-87d2-442f-978a-5de934ab0776" xlink:to="loc_us-gaap_SegmentDomain_31e7b776-87d2-442f-978a-5de934ab0776_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_274979cd-32f6-4a9f-9512-d5f9a31cca59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_31e7b776-87d2-442f-978a-5de934ab0776" xlink:to="loc_us-gaap_SegmentDomain_274979cd-32f6-4a9f-9512-d5f9a31cca59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_RegulatedOperationsMember_16a3d6a9-cc0a-446e-a92c-9e0b86f99096" xlink:href="ale-20210930.xsd#ale_RegulatedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_274979cd-32f6-4a9f-9512-d5f9a31cca59" xlink:to="loc_ale_RegulatedOperationsMember_16a3d6a9-cc0a-446e-a92c-9e0b86f99096" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETECleanEnergyMember_e1a5d5b9-3c03-4eb1-ac75-01d1be0e7936" xlink:href="ale-20210930.xsd#ale_ALLETECleanEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_274979cd-32f6-4a9f-9512-d5f9a31cca59" xlink:to="loc_ale_ALLETECleanEnergyMember_e1a5d5b9-3c03-4eb1-ac75-01d1be0e7936" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_369e4fae-d554-4929-85f3-0d2f907282ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_274979cd-32f6-4a9f-9512-d5f9a31cca59" xlink:to="loc_us-gaap_CorporateAndOtherMember_369e4fae-d554-4929-85f3-0d2f907282ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_5d67a0be-4d50-44f9-8c71-c2a2d036fa29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_17af37a6-118c-4d0a-8447-8789f575bede" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_5d67a0be-4d50-44f9-8c71-c2a2d036fa29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_5d67a0be-4d50-44f9-8c71-c2a2d036fa29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_5d67a0be-4d50-44f9-8c71-c2a2d036fa29" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_5d67a0be-4d50-44f9-8c71-c2a2d036fa29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_5d67a0be-4d50-44f9-8c71-c2a2d036fa29" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ResidentialMember_0d0f11e1-2bd6-4751-a1be-136b8660db60" xlink:href="ale-20210930.xsd#ale_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_ResidentialMember_0d0f11e1-2bd6-4751-a1be-136b8660db60" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CommercialMember_b0025077-202e-4567-bf6d-96aaf4892692" xlink:href="ale-20210930.xsd#ale_CommercialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_CommercialMember_b0025077-202e-4567-bf6d-96aaf4892692" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_MunicipalMember_5fb0997d-2a52-48f9-a0e0-28c46cdde6ed" xlink:href="ale-20210930.xsd#ale_MunicipalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_MunicipalMember_5fb0997d-2a52-48f9-a0e0-28c46cdde6ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_IndustrialMember_ccba6964-73f1-4922-9388-28e8414ab2e9" xlink:href="ale-20210930.xsd#ale_IndustrialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_IndustrialMember_ccba6964-73f1-4922-9388-28e8414ab2e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_OtherPowerSuppliersMember_ca7f9976-d378-4af4-b45b-43158058b603" xlink:href="ale-20210930.xsd#ale_OtherPowerSuppliersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_OtherPowerSuppliersMember_ca7f9976-d378-4af4-b45b-43158058b603" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_OtherMember_bc48816e-e0ae-4627-a57d-72e60e3bc4e3" xlink:href="ale-20210930.xsd#ale_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_OtherMember_bc48816e-e0ae-4627-a57d-72e60e3bc4e3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_LongtermPSAMember_85f1b23d-d0b3-4927-8cf1-452387973158" xlink:href="ale-20210930.xsd#ale_LongtermPSAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_LongtermPSAMember_85f1b23d-d0b3-4927-8cf1-452387973158" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CIPFinancialIncentiveMember_cc8d6367-7617-4770-9169-97fad0a1ff58" xlink:href="ale-20210930.xsd#ale_CIPFinancialIncentiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_CIPFinancialIncentiveMember_cc8d6367-7617-4770-9169-97fad0a1ff58" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_ALLETECleanEnergyOtherMember_0192e836-b8e0-4095-b2f5-0f757a037c9a" xlink:href="ale-20210930.xsd#ale_ALLETECleanEnergyOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_ALLETECleanEnergyOtherMember_0192e836-b8e0-4095-b2f5-0f757a037c9a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_LongtermContractMember_77cd8527-4ab3-4891-bded-13496d1eaa77" xlink:href="ale-20210930.xsd#ale_LongtermContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_LongtermContractMember_77cd8527-4ab3-4891-bded-13496d1eaa77" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ale_CorporateOtherOtherMember_8cb52d73-ba06-4793-9c2a-d32c530cd7ac" xlink:href="ale-20210930.xsd#ale_CorporateOtherOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_890a67c7-5959-406a-b3ac-5d60ee1bd99b" xlink:to="loc_ale_CorporateOtherOtherMember_8cb52d73-ba06-4793-9c2a-d32c530cd7ac" xlink:type="arc" order="10"/>
  </link:definitionLink>
</link:linkbase>
