<SEC-DOCUMENT>0001624067-15-000001.txt : 20150514
<SEC-HEADER>0001624067-15-000001.hdr.sgml : 20150514
<ACCEPTANCE-DATETIME>20150514190117
ACCESSION NUMBER:		0001624067-15-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150512
FILED AS OF DATE:		20150514
DATE AS OF CHANGE:		20150514

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Upland Software, Inc.
		CENTRAL INDEX KEY:			0001505155
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				272992077
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		401 CONGRESS AVE.
		STREET 2:		SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701
		BUSINESS PHONE:		855-944-7526

	MAIL ADDRESS:	
		STREET 1:		401 CONGRESS AVE.
		STREET 2:		SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Silverback Acquisition Corp
		DATE OF NAME CHANGE:	20101105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Mattox Timothy
		CENTRAL INDEX KEY:			0001624067

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36720
		FILM NUMBER:		15864851

	MAIL ADDRESS:	
		STREET 1:		401 CONGRESS AVE, SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_143164446725805.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-05-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001505155</issuerCik>
        <issuerName>Upland Software, Inc.</issuerName>
        <issuerTradingSymbol>UPLD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001624067</rptOwnerCik>
            <rptOwnerName>Mattox Timothy</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>401 CONGRESS AVE., SUITE 1850</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78701</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President &amp; COO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-05-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>181980</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-05-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>231980</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Unvested shares are subject to forfeiture to the Company. The shares will vest over a time period measured from a vesting commencement date of 1/1/2015 as follows: one-third of the shares vest on the first anniversary of the vesting commencement date, one-third of the shares vest in equal twelve installments on the corresponding day of each month over the period from the first anniversary of the vesting commencement date to the second anniversary of the vesting commencement date, one-third of the shares vest in equal twelve installments on the corresponding day of each month over the period from the second anniversary of the vesting commencement date to the third anniversary of the vesting commencement date, in each case subject to the reporting person continuing as a service provider to the Company through the applicable vesting date.</footnote>
        <footnote id="F2">Unvested shares are subject to forfeiture to the Company. the shares will vest over a time period measured from a vesting commencement date of 1/1/2015 as follows: The shares vest in equal twelve installments on the corresponding day of each month over the period from third anniversary of the vesting commencement date to the fourth anniversary of the vesting commencement date, in each case subject to the reporting person continuing as a service provider to the Company through the applicable vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kirk Larson, Attorney-in-Fact</signatureName>
        <signatureDate>2015-05-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
