EX-5.1

Exhibit 5.1

December 6, 2023

Unity Biotechnology, Inc.

285 East Grand Ave.

South San Francisco, CA 94080

Ladies and Gentlemen:

We have acted as counsel for Unity Biotechnology, Inc., a Delaware corporation (the “Company”), in connection with the filing with the Securities and Exchange Commission (the “Commission”) on the date hereof, under the Securities Act of 1933, as amended (the “Securities Act”), of a registration statement on Form S-3 (the “Registration Statement”) by the Company which registers the resale by the holders thereof of up to an aggregate of 2,271,580 shares of common stock of the Company, par value $0.0001 per share (the “Common Stock”), comprised of (i) 2,143,000 shares of Common Stock (the “Investor Warrant Shares”) issuable upon the exercise of warrants (the “Investor Warrants”) issued to certain holders pursuant to that certain inducement letter, dated November 9, 2023 between the Company and the investors named therein (the “Inducement Letter”); and (ii) 128,580 shares of Common Stock (the “Placement Agent Warrant Shares”) issuable upon exercise of warrants (the “Placement Agent Warrants”) issued to H.C. Wainwright & Co., LLC (the “Placement Agent”) or its designees as part of the Placement Agent’s compensation for serving as exclusive placement agent in connection with the transactions contemplated by the Inducement Letter. The Investor Warrant Shares and the Placement Agent Warrant Shares are referred to herein collectively as the “Securities.”

In rendering the opinions expressed herein, we have examined and relied upon the originals, or copies certified to our satisfaction, of (i) the Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws of the Company, as of the date hereof (“Company Charter Documents”); (ii) the Registration Statement and all exhibits thereto; (iii) the Investor Warrants; (iv) the Placement Agent Warrants; (v) a specimen of the Company’s Common Stock certificate; (vi) a certificate executed by an officer of the Company, dated as of the date hereof; and (vii) such other corporate records of the Company as we have deemed necessary or appropriate for purposes of the opinions hereafter expressed.

As to questions of fact material to the opinions expressed below, we have, without independent verification of their accuracy, relied to the extent we deemed reasonably appropriate upon the representations and warranties of the Company contained in such documents, records, certificates, instruments or representations furnished or made available to us by the Company.

In making the foregoing examinations, we have assumed (i) the genuineness of all signatures; (ii) the authenticity of all documents submitted to us as originals; (iii) the conformity to original documents of all documents submitted to us as certified or photostatic copies; (iv) that all agreements or instruments we have examined are the valid, binding and enforceable obligations of the parties thereto; and (v) that all factual information on which we have relied was accurate and complete.

We have also assumed that (i) the Company will continue to be incorporated and in existence and good standing in its jurisdiction of organization; (ii) the Registration Statement, and any amendments thereto (including post-effective amendments), will have become effective; (iii) no stop order of the Commission preventing or suspending the use of the prospectus contained in the Registration Statement or any prospectus supplement will have been issued; (iv) a prospectus properly describing the Securities offered thereby will have been delivered to the purchaser(s) of the Securities as required in accordance with applicable law; (v) all Securities will be offered, issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the prospectus and any prospectus supplement; (vi) any definitive purchase, underwriting or similar agreement with respect to any Securities offered will have been duly authorized and validly executed and delivered by the Company and the other parties thereto and will be an enforceable obligation of the parties thereto; (vii) upon effectiveness of the Registration Statement, there will be sufficient shares of Common Stock authorized under the Company Charter Documents and not otherwise reserved for issuance; and (viii) there will not have occurred any change in law or in the Company Charter Documents of the Company adversely affecting the Securities or the rights of the holders thereof.