<SEC-DOCUMENT>0001659617-19-000104.txt : 20190715
<SEC-HEADER>0001659617-19-000104.hdr.sgml : 20190715
<ACCEPTANCE-DATETIME>20190715161709
ACCESSION NUMBER:		0001659617-19-000104
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20190711
FILED AS OF DATE:		20190715
DATE AS OF CHANGE:		20190715

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			George Robert E.
		CENTRAL INDEX KEY:			0001674701

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37758
		FILM NUMBER:		19955362

	MAIL ADDRESS:	
		STREET 1:		2575 W. BELLFORT
		STREET 2:		SUITE 333
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77054

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Moleculin Biotech, Inc.
		CENTRAL INDEX KEY:			0001659617
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				474671999
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5300 MEMORIAL DRIVE
		STREET 2:		SUITE 950
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77007
		BUSINESS PHONE:		713-300-5160

	MAIL ADDRESS:	
		STREET 1:		5300 MEMORIAL DRIVE
		STREET 2:		SUITE 950
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77007
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_156322181376648.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-07-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001659617</issuerCik>
        <issuerName>Moleculin Biotech, Inc.</issuerName>
        <issuerTradingSymbol>MBRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001674701</rptOwnerCik>
            <rptOwnerName>George Robert E.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MOLECULIN BIOTECH, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>5300 MEMORIAL DR., SUITE 950</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77007</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.31</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-07-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>35000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2029-07-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>35000.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>120000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">(1) The options set forth in this table vest in four quarterly installments, subject to the grantee's continued service on the Company's Board of Directors on each vesting date.</footnote>
        <footnote id="F2">(2) The options were issued in connection with the reporting person's Board of Director service to the Company.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jonathan P. Foster by Power of Attorney</signatureName>
        <signatureDate>2019-07-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>poa.htm
<DESCRIPTION>POWER OF ATTORNEY FOR: ROBERT GEORGE, POA
<TEXT>
<!-- Document created using Workiva -->
<html>
<body>
<pre>
Exhibit 24

POWER OF ATTORNEY

The undersigned, as a person who are required to file with the Securities Exchange Commission ("SEC") public reports disclosing their holdings of, and transactions in, the equity securities of Moleculin Biotech, Inc. (the "Company") under Section 16 of the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (the "1934 Act"), hereby constitutes and appoints each of Walter Klemp and Jonathan Foster as the undersigned's true and lawful attorney-in-fact to:

1.    Complete and execute Forms 3, 4 and 5 and other forms and all amendments thereto as such attorney-in-fact shall in his discretion determine to be required or advisable pursuant to Section 16 of the 1934 Act, as a consequence of the undersigned's ownership, acquisition or disposition of any equity securities of the Company; and

2.    Do all acts necessary in order to file such forms with the SEC, any securities exchange or national association, the Company and such other person or agency as the attorney-in-fact shall deem appropriate.

Each of said attorneys-in-fact shall individually have the authority to act in accordance with this Power of Attorney. The undersigned hereby ratifies and confirms all that each of said attorneys-in-fact and agents shall do or cause to be done by virtue hereof. The undersigned acknowledges that each of the foregoing attorneys in-fact, in serving in such capacity at the request of the undersigned, is not assuming, nor is the Company assuming, any of the undersigned's responsibilities to comply with Section 16 of the 1934 Act.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 3, 4, and 5 with respect to the undersigned's holdings of and transactions in securities issued by the Company, unless earlier revoked by the undersigned in a signed writing delivered to the Company and any one of the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 29th day of September, 2016.

Signature: /s/ Robert E. George

Print Name: Robert E. George
</pre>
</body>
</html>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
