<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-03-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001301787</issuerCik>
        <issuerName>BlueLinx Holdings Inc.</issuerName>
        <issuerTradingSymbol>BXC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000947822</rptOwnerCik>
            <rptOwnerName>FEINBERG STEPHEN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CERBERUS CAPITAL MANAGEMENT, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>875 THIRD AVENUE, 11TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-03-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13486288</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>47138267</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By limited liability company</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Cerberus ABP Investor LLC (&quot;Cerberus ABP&quot;) is the holder of 47,138,267 shares of common stock, par value $0.01 per share (the &quot;Common Stock&quot;), of BlueLinx Holdings Inc. (the &quot;Company&quot;).  Stephen Feinberg, through one or more intermediate entities, possesses the sole power to vote and the sole power to direct the disposition of all securities of the Company held by Cerberus ABP.  Mr. Feinberg's interest in such securities is limited to the extent of his pecuniary interest in Cerberus ABP, if any.</footnote>
        <footnote id="F2">Howard S. Cohen, the chairman of the Company's board of directors, is a senior advisor to an affiliate of Cerberus ABP.  Mr. Cohen, according to a Form 4 filed with the U.S. Securities and Exchange Commission (the &quot;SEC&quot;) on April 1, 2013, holds 1,303,632 shares of Common Stock and options to purchase 750,000 shares of Common Stock at an exercise price of $4.66 per share.  Mr. Feinberg disclaims all pecuniary interest in, and beneficial ownership of, any of the Company's securities held by Mr. Cohen.</footnote>
        <footnote id="F3">On March 28, 2013, Cerberus ABP purchased from the Company 13,486,288 shares of Common Stock at a purchase price of $1.75 per share pursuant to the terms of the Company's rights offering.  The terms of the rights offering are described in a prospectus filed by the Company with the SEC on March 5, 2013.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Stephen Feinberg</signatureName>
        <signatureDate>2013-04-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
