<SEC-DOCUMENT>0002023849-25-000003.txt : 20250929
<SEC-HEADER>0002023849-25-000003.hdr.sgml : 20250929
<ACCEPTANCE-DATETIME>20250929170006
ACCESSION NUMBER:		0002023849-25-000003
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250925
FILED AS OF DATE:		20250929
DATE AS OF CHANGE:		20250929

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Ruddy Marcella K.
		CENTRAL INDEX KEY:			0002023849
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38537
		FILM NUMBER:		251357071

	MAIL ADDRESS:	
		STREET 1:		C/O TECTONIC THERAPEUTIC, INC.
		STREET 2:		490 ARSENAL WAY, SUITE 210
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Tectonic Therapeutic, Inc.
		CENTRAL INDEX KEY:			0001681087
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				810710585
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		490 ARSENAL WAY
		STREET 2:		SUITE 210
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472
		BUSINESS PHONE:		(339) 666-3320

	MAIL ADDRESS:	
		STREET 1:		490 ARSENAL WAY
		STREET 2:		SUITE 210
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AVROBIO, Inc.
		DATE OF NAME CHANGE:	20180131

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AvroBio, Inc.
		DATE OF NAME CHANGE:	20160729
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4-09292025_050903.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-09-25</periodOfReport>

    <issuer>
        <issuerCik>0001681087</issuerCik>
        <issuerName>Tectonic Therapeutic, Inc.</issuerName>
        <issuerTradingSymbol>TECX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002023849</rptOwnerCik>
            <rptOwnerName>Ruddy Marcella K.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O TECTONIC THERAPEUTIC, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>490 ARSENAL WAY, SUITE 210</rptOwnerStreet2>
            <rptOwnerCity>WATERTOWN</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02472</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Chief Medical Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-09-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5370</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>55311</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>14.71</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-09-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2035-09-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9750</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9750</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These shares are represented by restricted stock units. Each restricted stock unit represents a contingent right to receive one share of common stock of the Issuer. The shares shall vest in 3 equal annual installments on each of September 25, 2026, September 25, 2027 and September 25, 2028, subject to the Reporting Person's continued service to the Issuer on each such vesting date.</footnote>
        <footnote id="F2">The shares subject to the option vest in 48 equal monthly installments beginning on October 25, 2025, subject to the Reporting Person's continued service to the Issuer on each such vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Daniel Lochner, Attorney-in-Fact</signatureName>
        <signatureDate>2025-09-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
