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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-05-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001164552</issuerCik>
        <issuerName>Green Energy Management Services Holdings, Inc.</issuerName>
        <issuerTradingSymbol>GRMS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001518382</rptOwnerCik>
            <rptOwnerName>Ulfers Ronald P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GREEN ENERGY MANAGEMENT SERVICES</rptOwnerStreet1>
            <rptOwnerStreet2>HOLDINGS, INC., 381 TEANECK ROAD</rptOwnerStreet2>
            <rptOwnerCity>TEANECK</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07666</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman, President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, $0.0001 par value</value>
            </securityTitle>
            <transactionDate>
                <value>2011-05-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>40000000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>63859803</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">40,000,000 shares were transferred by certain stockholders of the Issuer to MCA (as defined below) in consideration of the Reporting Person being appointed as the Chairman, President and Chief Executive Officer and a director of the Issuer on April 6, 2011.</footnote>
        <footnote id="F2">The Reporting Person is the sole member of RPU Services LLC (&quot;RPU&quot;) and Mountain Construction Advisors, LLC (&quot;MCA&quot;).</footnote>
        <footnote id="F3">As of the date of this report, RPU beneficially owns directly 2,000,000 shares of the Issuer.</footnote>
        <footnote id="F4">As of the date of this report, MCA beneficially owns directly 61,859,803 shares of the Issuer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Robert Weinstein, as attorney-in-fact for Ronald P. Ulfers, Jr.</signatureName>
        <signatureDate>2011-05-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
