<SEC-DOCUMENT>0001666138-17-000077.txt : 20170908
<SEC-HEADER>0001666138-17-000077.hdr.sgml : 20170908
<ACCEPTANCE-DATETIME>20170908172402
ACCESSION NUMBER:		0001666138-17-000077
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170906
FILED AS OF DATE:		20170908
DATE AS OF CHANGE:		20170908

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Waltz William E Jr.
		CENTRAL INDEX KEY:			0001674332

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37793
		FILM NUMBER:		171077349

	MAIL ADDRESS:	
		STREET 1:		16100 SOUTH LATHROP AVENUE
		CITY:			HARVEY
		STATE:			IL
		ZIP:			60426

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Atkore International Group Inc.
		CENTRAL INDEX KEY:			0001666138
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
		IRS NUMBER:				900631463
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		16100 SOUTH LATHROP AVENUE
		CITY:			HARVEY
		STATE:			IL
		ZIP:			60426
		BUSINESS PHONE:		7083391610

	MAIL ADDRESS:	
		STREET 1:		16100 SOUTH LATHROP AVENUE
		CITY:			HARVEY
		STATE:			IL
		ZIP:			60426
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_150490582960522.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-09-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001666138</issuerCik>
        <issuerName>Atkore International Group Inc.</issuerName>
        <issuerTradingSymbol>ATKR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001674332</rptOwnerCik>
            <rptOwnerName>Waltz William E Jr.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>16100 SOUTH LATHROP AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HARVEY</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60426</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP &amp; Pres., Conduit &amp; Fittings</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2017-09-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>68846</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>88548</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reflects the award of restricted stock units, which are scheduled to vest based on continued employment through the third anniversary of the grant date or termination due to death or disability prior to such date.   In the event of earlier termination without cause, a prorated award shall vest.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Daniel S. Kelly, Attorney-in-Fact for William E. Waltz, Jr.</signatureName>
        <signatureDate>2017-09-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
