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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e183b-29b0-7c69-9684-160e6dd3f21a,g:e866f93b-4e74-4031-95ad-6b572090f740-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:atkr="http://atkore.com/20260626" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://atkore.com/20260626">
  <xs:import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2026" schemaLocation="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="atkr-20260626_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="atkr-20260626_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="atkr-20260626_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="atkr-20260626_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://atkore.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS">
        <link:definition>9952151 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME">
        <link:definition>9952152 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDBALANCESHEETS" roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS">
        <link:definition>9952153 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical">
        <link:definition>9952154 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS">
        <link:definition>9952155 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTOFCHANGESINSHAREHOLDERSEQUITY" roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTOFCHANGESINSHAREHOLDERSEQUITY">
        <link:definition>9952156 - Statement - CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS&#8217; EQUITY</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BASISOFPRESENTATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES" roleURI="http://atkore.com/role/BASISOFPRESENTATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES">
        <link:definition>9952157 - Disclosure - BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUEFROMCONTRACTSWITHCUSTOMERS" roleURI="http://atkore.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERS">
        <link:definition>9952158 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DIVESTITURES" roleURI="http://atkore.com/role/DIVESTITURES">
        <link:definition>9952159 - Disclosure - DIVESTITURES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EQUITYMETHODINVESTMENT" roleURI="http://atkore.com/role/EQUITYMETHODINVESTMENT">
        <link:definition>9952160 - Disclosure - EQUITY METHOD INVESTMENT</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="POSTRETIREMENTBENEFITS" roleURI="http://atkore.com/role/POSTRETIREMENTBENEFITS">
        <link:definition>9952161 - Disclosure - POSTRETIREMENT BENEFITS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGES" roleURI="http://atkore.com/role/RESTRUCTURINGCHARGES">
        <link:definition>9952162 - Disclosure - RESTRUCTURING CHARGES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHEREXPENSEINCOMENET" roleURI="http://atkore.com/role/OTHEREXPENSEINCOMENET">
        <link:definition>9952163 - Disclosure - OTHER EXPENSE (INCOME), NET</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXES" roleURI="http://atkore.com/role/INCOMETAXES">
        <link:definition>9952164 - Disclosure - INCOME TAXES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EARNINGSPERSHARE" roleURI="http://atkore.com/role/EARNINGSPERSHARE">
        <link:definition>9952165 - Disclosure - EARNINGS PER SHARE</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCUMULATEDOTHERCOMPREHENSIVELOSS" roleURI="http://atkore.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSS">
        <link:definition>9952166 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESNET" roleURI="http://atkore.com/role/INVENTORIESNET">
        <link:definition>9952167 - Disclosure - INVENTORIES, NET</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PROPERTYPLANTANDEQUIPMENT" roleURI="http://atkore.com/role/PROPERTYPLANTANDEQUIPMENT">
        <link:definition>9952168 - Disclosure - PROPERTY, PLANT AND EQUIPMENT</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETS" roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETS">
        <link:definition>9952169 - Disclosure - GOODWILL AND INTANGIBLE ASSETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBT" roleURI="http://atkore.com/role/DEBT">
        <link:definition>9952170 - Disclosure - DEBT</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTS" roleURI="http://atkore.com/role/FAIRVALUEMEASUREMENTS">
        <link:definition>9952171 - Disclosure - FAIR VALUE MEASUREMENTS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="COMMITMENTSANDCONTINGENCIES" roleURI="http://atkore.com/role/COMMITMENTSANDCONTINGENCIES">
        <link:definition>9952172 - Disclosure - COMMITMENTS AND CONTINGENCIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GUARANTEES" roleURI="http://atkore.com/role/GUARANTEES">
        <link:definition>9952173 - Disclosure - GUARANTEES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATION" roleURI="http://atkore.com/role/SEGMENTINFORMATION">
        <link:definition>9952174 - Disclosure - SEGMENT INFORMATION</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUBSEQUENTEVENTS" roleURI="http://atkore.com/role/SUBSEQUENTEVENTS">
        <link:definition>9952175 - Disclosure - SUBSEQUENT EVENTS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BASISOFPRESENTATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies" roleURI="http://atkore.com/role/BASISOFPRESENTATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies">
        <link:definition>9955511 - Disclosure - BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BASISOFPRESENTATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables" roleURI="http://atkore.com/role/BASISOFPRESENTATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables">
        <link:definition>9955512 - Disclosure - BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DIVESTITURESTables" roleURI="http://atkore.com/role/DIVESTITURESTables">
        <link:definition>9955513 - Disclosure - DIVESTITURES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="POSTRETIREMENTBENEFITSTables" roleURI="http://atkore.com/role/POSTRETIREMENTBENEFITSTables">
        <link:definition>9955514 - Disclosure - POSTRETIREMENT BENEFITS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESTables" roleURI="http://atkore.com/role/RESTRUCTURINGCHARGESTables">
        <link:definition>9955515 - Disclosure - RESTRUCTURING CHARGES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHEREXPENSEINCOMENETTables" roleURI="http://atkore.com/role/OTHEREXPENSEINCOMENETTables">
        <link:definition>9955516 - Disclosure - OTHER EXPENSE (INCOME), NET (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EARNINGSPERSHARETables" roleURI="http://atkore.com/role/EARNINGSPERSHARETables">
        <link:definition>9955517 - Disclosure - EARNINGS PER SHARE (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCUMULATEDOTHERCOMPREHENSIVELOSSTables" roleURI="http://atkore.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSTables">
        <link:definition>9955518 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESNETTables" roleURI="http://atkore.com/role/INVENTORIESNETTables">
        <link:definition>9955519 - Disclosure - INVENTORIES, NET (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PROPERTYPLANTANDEQUIPMENTTables" roleURI="http://atkore.com/role/PROPERTYPLANTANDEQUIPMENTTables">
        <link:definition>9955520 - Disclosure - PROPERTY, PLANT AND EQUIPMENT (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSTables" roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSTables">
        <link:definition>9955521 - Disclosure - GOODWILL AND INTANGIBLE ASSETS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTTables" roleURI="http://atkore.com/role/DEBTTables">
        <link:definition>9955522 - Disclosure - DEBT (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTSTables" roleURI="http://atkore.com/role/FAIRVALUEMEASUREMENTSTables">
        <link:definition>9955523 - Disclosure - FAIR VALUE MEASUREMENTS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONTables" roleURI="http://atkore.com/role/SEGMENTINFORMATIONTables">
        <link:definition>9955524 - Disclosure - SEGMENT INFORMATION (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUEFROMCONTRACTSWITHCUSTOMERSDetails" roleURI="http://atkore.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSDetails">
        <link:definition>9955525 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUEFROMCONTRACTSWITHCUSTOMERSDetails_1" roleURI="http://atkore.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSDetails_1">
        <link:definition>9955525 - Disclosure - REVENUE FROM CONTRACTS WITH CUSTOMERS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DIVESTITURESScheduleofSellingPriceAllocationDetails" roleURI="http://atkore.com/role/DIVESTITURESScheduleofSellingPriceAllocationDetails">
        <link:definition>9955526 - Disclosure - DIVESTITURES - Schedule of Selling Price Allocation (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DIVESTITURESNarrativeDetails" roleURI="http://atkore.com/role/DIVESTITURESNarrativeDetails">
        <link:definition>9955527 - Disclosure - DIVESTITURES - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DIVESTITURESScheduleofConsiderationreceivedDetails" roleURI="http://atkore.com/role/DIVESTITURESScheduleofConsiderationreceivedDetails">
        <link:definition>9955528 - Disclosure - DIVESTITURES - Schedule of Consideration received (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EQUITYMETHODINVESTMENTDetails" roleURI="http://atkore.com/role/EQUITYMETHODINVESTMENTDetails">
        <link:definition>9955529 - Disclosure - EQUITY METHOD INVESTMENT (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="POSTRETIREMENTBENEFITSDetails" roleURI="http://atkore.com/role/POSTRETIREMENTBENEFITSDetails">
        <link:definition>9955530 - Disclosure - POSTRETIREMENT BENEFITS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESRestructuringReservesDetails" roleURI="http://atkore.com/role/RESTRUCTURINGCHARGESRestructuringReservesDetails">
        <link:definition>9955531 - Disclosure - RESTRUCTURING CHARGES - Restructuring Reserves (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESAsaComponentofSellingGeneralandAdministrativeDetails" roleURI="http://atkore.com/role/RESTRUCTURINGCHARGESAsaComponentofSellingGeneralandAdministrativeDetails">
        <link:definition>9955532 - Disclosure - RESTRUCTURING CHARGES - As a Component of Selling, General and Administrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESNarrativeDetails" roleURI="http://atkore.com/role/RESTRUCTURINGCHARGESNarrativeDetails">
        <link:definition>9955533 - Disclosure - RESTRUCTURING CHARGES - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHEREXPENSEINCOMENETScheduleofOtherExpenseIncomeNetDetails" roleURI="http://atkore.com/role/OTHEREXPENSEINCOMENETScheduleofOtherExpenseIncomeNetDetails">
        <link:definition>9955534 - Disclosure - OTHER EXPENSE (INCOME), NET - Schedule of Other Expense (Income), Net (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHEREXPENSEINCOMENETNarrativeDetails" roleURI="http://atkore.com/role/OTHEREXPENSEINCOMENETNarrativeDetails">
        <link:definition>9955535 - Disclosure - OTHER EXPENSE (INCOME), NET - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXESDetails" roleURI="http://atkore.com/role/INCOMETAXESDetails">
        <link:definition>9955536 - Disclosure - INCOME TAXES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EARNINGSPERSHAREDetails" roleURI="http://atkore.com/role/EARNINGSPERSHAREDetails">
        <link:definition>9955537 - Disclosure - EARNINGS PER SHARE (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails" roleURI="http://atkore.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails">
        <link:definition>9955538 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESNETNarrativeDetails" roleURI="http://atkore.com/role/INVENTORIESNETNarrativeDetails">
        <link:definition>9955539 - Disclosure - INVENTORIES, NET - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESNETScheduleofCompanyInventoriesDetails" roleURI="http://atkore.com/role/INVENTORIESNETScheduleofCompanyInventoriesDetails">
        <link:definition>9955540 - Disclosure - INVENTORIES, NET - Schedule of Company Inventories (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails" roleURI="http://atkore.com/role/PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails">
        <link:definition>9955541 - Disclosure - PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PROPERTYPLANTANDEQUIPMENTNarrativeDetails" roleURI="http://atkore.com/role/PROPERTYPLANTANDEQUIPMENTNarrativeDetails">
        <link:definition>9955542 - Disclosure - PROPERTY, PLANT AND EQUIPMENT - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSGoodwillDetails" roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSGoodwillDetails">
        <link:definition>9955543 - Disclosure - GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSNarrativeDetails" roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSNarrativeDetails">
        <link:definition>9955544 - Disclosure - GOODWILL AND INTANGIBLE ASSETS - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails" roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails">
        <link:definition>9955545 - Disclosure - GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSExpectedAmortizationExpenseDetails" roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSExpectedAmortizationExpenseDetails">
        <link:definition>9955546 - Disclosure - GOODWILL AND INTANGIBLE ASSETS - Expected Amortization Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTScheduleofDebtDetails" roleURI="http://atkore.com/role/DEBTScheduleofDebtDetails">
        <link:definition>9955547 - Disclosure - DEBT - Schedule of Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTScheduleofDebtDetails_1" roleURI="http://atkore.com/role/DEBTScheduleofDebtDetails_1">
        <link:definition>9955547 - Disclosure - DEBT - Schedule of Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTNarrativeDetails" roleURI="http://atkore.com/role/DEBTNarrativeDetails">
        <link:definition>9955548 - Disclosure - DEBT - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTSNarrativeDetails" roleURI="http://atkore.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails">
        <link:definition>9955549 - Disclosure - FAIR VALUE MEASUREMENTS - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTSAssetsandLiabilitiesMeasuredatFairValueDetails" roleURI="http://atkore.com/role/FAIRVALUEMEASUREMENTSAssetsandLiabilitiesMeasuredatFairValueDetails">
        <link:definition>9955550 - Disclosure - FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTSEstimatedFairValueofFinancialInstrumentsNotCarriedatFairValueDetails" roleURI="http://atkore.com/role/FAIRVALUEMEASUREMENTSEstimatedFairValueofFinancialInstrumentsNotCarriedatFairValueDetails">
        <link:definition>9955551 - Disclosure - FAIR VALUE MEASUREMENTS - Estimated Fair Value of Financial Instruments Not Carried at Fair Value (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="COMMITMENTSANDCONTINGENCIESDetails" roleURI="http://atkore.com/role/COMMITMENTSANDCONTINGENCIESDetails">
        <link:definition>9955552 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GUARANTEESDetails" roleURI="http://atkore.com/role/GUARANTEESDetails">
        <link:definition>9955553 - Disclosure - GUARANTEES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONNarrativeDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONNarrativeDetails">
        <link:definition>9955554 - Disclosure - SEGMENT INFORMATION - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONScheduleofSegmentInformationDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONScheduleofSegmentInformationDetails">
        <link:definition>9955555 - Disclosure - SEGMENT INFORMATION -Schedule of Segment Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONScheduleofReconciliationofNetSalesDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONScheduleofReconciliationofNetSalesDetails">
        <link:definition>9955556 - Disclosure - SEGMENT INFORMATION - Schedule of Reconciliation of Net Sales (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONReconciliationofOperatingSegmentIncomeDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONReconciliationofOperatingSegmentIncomeDetails">
        <link:definition>9955557 - Disclosure - SEGMENT INFORMATION - Reconciliation of Operating Segment Income (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONScheduleofSegmentInformationofCapitalExpendituresandAssetsDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONScheduleofSegmentInformationofCapitalExpendituresandAssetsDetails">
        <link:definition>9955558 - Disclosure - SEGMENT INFORMATION - Schedule of Segment Information of Capital Expenditures and Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONScheduleofNetSalesByGeographyDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONScheduleofNetSalesByGeographyDetails">
        <link:definition>9955559 - Disclosure - SEGMENT INFORMATION - Schedule of Net Sales By Geography (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONScheduleofNetSalesFromExternalCustomersbyProductCategoryDetails" roleURI="http://atkore.com/role/SEGMENTINFORMATIONScheduleofNetSalesFromExternalCustomersbyProductCategoryDetails">
        <link:definition>9955560 - Disclosure - SEGMENT INFORMATION - Schedule of Net Sales From External Customers by Product Category (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUBSEQUENTEVENTSDetails" roleURI="http://atkore.com/role/SUBSEQUENTEVENTSDetails">
        <link:definition>9955561 - Disclosure - SUBSEQUENT EVENTS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="atkr_OperatingAndFinanceLeaseRightOfUseAssetNet" abstract="false" name="OperatingAndFinanceLeaseRightOfUseAssetNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_OperatingAndFinanceLeaseLiabilityCurrent" abstract="false" name="OperatingAndFinanceLeaseLiabilityCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_OperatingAndFinanceLeaseLiabilityNoncurrent" abstract="false" name="OperatingAndFinanceLeaseLiabilityNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_ProvisionForDoubtfulAccountsAndInventory" abstract="false" name="ProvisionForDoubtfulAccountsAndInventory" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_ChangesInOperatingAssetsAndLiabilitiesNetOfEffectsFromAcquisitionsAbstract" abstract="true" name="ChangesInOperatingAssetsAndLiabilitiesNetOfEffectsFromAcquisitionsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="atkr_IncreaseDecreaseInLegalSettlementExpense" abstract="false" name="IncreaseDecreaseInLegalSettlementExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_IncreaseDecreaseInLeaseAssetsAndLiabilities" abstract="false" name="IncreaseDecreaseInLeaseAssetsAndLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_IncreaseDecreaseOfRevenueEconomicValueOfTaxCreditsToBeTransferred" abstract="false" name="IncreaseDecreaseOfRevenueEconomicValueOfTaxCreditsToBeTransferred" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_IncreaseDecreaseInCostOfSalesEconomicValueOfTaxCreditsToBeTransferred" abstract="false" name="IncreaseDecreaseInCostOfSalesEconomicValueOfTaxCreditsToBeTransferred" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_LiabilityForCreditsToBeTransferred" abstract="false" name="LiabilityForCreditsToBeTransferred" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_RevenueFromContractWithCustomerPaymentTerm" abstract="false" name="RevenueFromContractWithCustomerPaymentTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="atkr_VergoGalvaNVAndVergoCoatingSRLMember" abstract="true" name="VergoGalvaNVAndVergoCoatingSRLMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_TectronTubeMember" abstract="true" name="TectronTubeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_NorthwestPolymersMember" abstract="true" name="NorthwestPolymersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationNotesReceivable" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationNotesReceivable" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationHoldbackReceivable" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationHoldbackReceivable" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationNetAssetsDivested" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationNetAssetsDivested" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationNetWorkingCapitalTrueUp" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationNetWorkingCapitalTrueUp" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_OperationsInRussiaMember" abstract="true" name="OperationsInRussiaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_HighDensityPolyethyleneBusinessMember" abstract="true" name="HighDensityPolyethyleneBusinessMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_InfraPipesSolutionsU.SCorp.Member" abstract="true" name="InfraPipesSolutionsU.SCorp.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationWorkingCapital" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationWorkingCapital" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationRightOfUseAssets" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationRightOfUseAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationLeaseLiability" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationLeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_EquityMethodInvestmentAdditionalCommittedAmount" abstract="false" name="EquityMethodInvestmentAdditionalCommittedAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationAccountsReceivableNet" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationAccountsReceivableNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationRightOfUseLiabilities" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationRightOfUseLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationAdditionalTaxExpense" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationAdditionalTaxExpense" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationDisallowedLossOnTransaction" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationDisallowedLossOnTransaction" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationWrittenOffRelatedToDeferredTax" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationWrittenOffRelatedToDeferredTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationEquityMethodInvestmentReceived" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationEquityMethodInvestmentReceived" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationEarnoutDerivative" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationEarnoutDerivative" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_EquityMethodInvestmentAdditionalCommittedAmountCashProvidedAtClosing" abstract="false" name="EquityMethodInvestmentAdditionalCommittedAmountCashProvidedAtClosing" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_EquityMethodInvestmentAdditionalCommittedAmountCashPayableAtClosing" abstract="false" name="EquityMethodInvestmentAdditionalCommittedAmountCashPayableAtClosing" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_ElectricalSegmentMember" abstract="true" name="ElectricalSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SafetyInfrastructureSegmentMember" abstract="true" name="SafetyInfrastructureSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_RestructuringReserveSettledWithOrWithoutCash" abstract="false" name="RestructuringReserveSettledWithOrWithoutCash" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_RestructuringChargesNet" abstract="false" name="RestructuringChargesNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_LongLivedAssetsHeldForUseMember" abstract="true" name="LongLivedAssetsHeldForUseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_OperatingLeaseRightOfUseAssetMember" abstract="true" name="OperatingLeaseRightOfUseAssetMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_ForeignExchangeGainLossOnIntercompanyLoans" abstract="false" name="ForeignExchangeGainLossOnIntercompanyLoans" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DisposalGroupIncludingDiscontinuedOperationValuationAllowance" abstract="false" name="DisposalGroupIncludingDiscontinuedOperationValuationAllowance" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_FIFOInventoryHigherLowerThanReported" abstract="false" name="FIFOInventoryHigherLowerThanReported" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_InventoryRawMaterialsAndPurchasedPartsNetOfValuationReserves" abstract="false" name="InventoryRawMaterialsAndPurchasedPartsNetOfValuationReserves" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_ABLCreditFacilityMember" abstract="true" name="ABLCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SeniorSecuredTermLoanFacilityDueSeptember292032Member" abstract="true" name="SeniorSecuredTermLoanFacilityDueSeptember292032Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SeniorNotesDueJune12031Member" abstract="true" name="SeniorNotesDueJune12031Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_LongTermDebtNetOfUnamortizedDiscount" abstract="false" name="LongTermDebtNetOfUnamortizedDiscount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_AmendedABLCreditFacilityMember" abstract="true" name="AmendedABLCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SeniorTermLoanFacilityDueMay262028Member" abstract="true" name="SeniorTermLoanFacilityDueMay262028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SeniorTermLoanFacilityDueSeptember292032Member" abstract="true" name="SeniorTermLoanFacilityDueSeptember292032Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SeniorNotesDueJune2031Member" abstract="true" name="SeniorNotesDueJune2031Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_AtkoreInternationalInc.Member" abstract="true" name="AtkoreInternationalInc.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DebtInstrumentInterestPeriodAxis" abstract="true" name="DebtInstrumentInterestPeriodAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="atkr_DebtInstrumentInterestPeriodDomain" abstract="true" name="DebtInstrumentInterestPeriodDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DebtInstrumentInterestPeriodOneMember" abstract="true" name="DebtInstrumentInterestPeriodOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DebtInstrumentInterestPeriodTwoMember" abstract="true" name="DebtInstrumentInterestPeriodTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DebtInstrumentInterestPeriodThreeMember" abstract="true" name="DebtInstrumentInterestPeriodThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_TermSecuredOvernightFinancingRateSOFRMember" abstract="true" name="TermSecuredOvernightFinancingRateSOFRMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DebtInstrumentVariableRateCreditSpreadAdjustment" abstract="false" name="DebtInstrumentVariableRateCreditSpreadAdjustment" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="atkr_DebtInstrumentExtendedTermPeriodPriorToMaturityDate" abstract="false" name="DebtInstrumentExtendedTermPeriodPriorToMaturityDate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="atkr_LineOfCreditFacilityTermOutstandingObligationsThresholdAmount" abstract="false" name="LineOfCreditFacilityTermOutstandingObligationsThresholdAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_DebtInstrumentVariableRateFloor" abstract="false" name="DebtInstrumentVariableRateFloor" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="atkr_DebtInstrumentAmortizationRate" abstract="false" name="DebtInstrumentAmortizationRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="atkr_PutativeClassOfDirectPurchaserPlaintiffsMember" abstract="true" name="PutativeClassOfDirectPurchaserPlaintiffsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_PutativeClassOfNonConverterSellerPurchaserPlaintiffsMember" abstract="true" name="PutativeClassOfNonConverterSellerPurchaserPlaintiffsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_PutativeClassOfEndUserPlaintiffsMember" abstract="true" name="PutativeClassOfEndUserPlaintiffsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_IncomeLossFromContinuingOperationsAdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationEBITDA" abstract="false" name="IncomeLossFromContinuingOperationsAdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationEBITDA" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_SafetyAndInfrastructureSegmentMember" abstract="true" name="SafetyAndInfrastructureSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_SellingGeneralAndAdministrativeExpenseUnallocated" abstract="false" name="SellingGeneralAndAdministrativeExpenseUnallocated" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_TransactionCosts" abstract="false" name="TransactionCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_GainLossOnAssetsHeldForSale" abstract="false" name="GainLossOnAssetsHeldForSale" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="atkr_OtherAmericasExcludingUnitedStatesMember" abstract="true" name="OtherAmericasExcludingUnitedStatesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_MetalElectricalConduitAndFittingsMember" abstract="true" name="MetalElectricalConduitAndFittingsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_ElectricalCableAndFlexibleConduitMember" abstract="true" name="ElectricalCableAndFlexibleConduitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_PlasticPipeAndConduitMember" abstract="true" name="PlasticPipeAndConduitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_OtherElectricalProductsMember" abstract="true" name="OtherElectricalProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_MechanicalPipeMember" abstract="true" name="MechanicalPipeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_OtherSafetyInfrastructureProductsMember" abstract="true" name="OtherSafetyInfrastructureProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_PrysmianS.p.A.Member" abstract="true" name="PrysmianS.p.A.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_MarkLampsMember" abstract="true" name="MarkLampsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="atkr_DanKellyMember" abstract="true" name="DanKellyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
