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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-07-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001396633</issuerCik>
        <issuerName>SUMMER ENERGY HOLDINGS INC</issuerName>
        <issuerTradingSymbol>SUME</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001116185</rptOwnerCik>
            <rptOwnerName>LEIBMAN NEIL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>800 BERING DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 260</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77057</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-07-20</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.52</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>77372</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares were purchased at a price of $1.5154 per share.</footnote>
        <footnote id="F2">The reported securities were purchased by NORTHEAST OPCO, LLC, a Texas limited liability company of which the Reporting Person is an officer and control person as well as a 20% owner.  The Reporting Person disclaims beneficial ownership of the shares of common stock held by NORTHEAST OPCO, LLC, except to the extent of his pecuniary interest therein. The purchases were made pursuant to a 10b5-1 trading plan adopted by NORTHEAST OPCO, LLC, on June 19, 2015.</footnote>
    </footnotes>

    <remarks>By Alexander N. Pearson, pursuant to a power of attorney dated December 12, 2012, included as Exhibit 24.1 to Schedule 13G filed on December 12, 2012.</remarks>

    <ownerSignature>
        <signatureName>/s/ NEIL LEIBMAN</signatureName>
        <signatureDate>2017-07-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
