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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-08-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000771497</issuerCik>
        <issuerName>ABM INDUSTRIES INC /DE/</issuerName>
        <issuerTradingSymbol>ABM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001433554</rptOwnerCik>
            <rptOwnerName>McConnell Sarah H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>551 FIFTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10176</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP/GEN. COUNSEL/CORP. SECTY.</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-08-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>183</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.71</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>41494</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Dividend equivalent rights (DERs) accrued on the restricted stock units granted under the 2006 Equity Incentive Plan and, if applicable, on performance shares granted under the 2006 Equity Plan, to the extent that such performance shares have been earned under the performance share program relating to such shares. DERs vest in the same manner as the awards to which they relate. Each DER is the economic equivalent of one share of ABM common stock.</footnote>
        <footnote id="F2">Includes 17,776 unvested RSUs, 9,277 vested RSUs, the receipt of which has been deferred and DERS relating to the RSUs, adjusted to reflect the cumulative effect of fractional shares, 1,175 performance shares earned but not vested with respect to performance shares granted on 3/8/2012, 1,276 performance shares earned but not vested with respect to performance shares granted on 1/14/2013, and DERs related thereto.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Sarah H. McConnell, by power of attorney</signatureName>
        <signatureDate>2014-08-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
