EX-5.1

Exhibit 5.1

LOGO

Josh Seidenfeld

+1 650 843 5862

jseidenfeld@cooley.com

March 28, 2022

AN2 Therapeutics, Inc.

1800 El Camino Real, Suite D

Menlo Park, CA 94027

Ladies and Gentlemen:

We have acted as counsel to AN2 Therapeutics, Inc., a Delaware corporation (the “Company”), in connection with the filing of a registration statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission covering the offering of up to 6,248,408 shares (the “Shares”) of the Company’s common stock, par value $0.00001 per share (the “Common Stock”), consisting of (i) 1,637,488 shares of Common Stock issuable pursuant to the Company’s 2017 Equity Incentive Plan, as amended (the “2017 EIP”), (ii) 4,423,920 shares of Common Stock issuable pursuant to the Company’s 2022 Equity Incentive Plan (the “2022 EIP”), and (iii) 187,000 shares of Common Stock issuable pursuant to the Company’s 2022 Employee Stock Purchase Plan (together with the Company’s 2017 EIP and 2022 EIP, the “Plans”).

In connection with this opinion, we have examined and relied upon (i) the Registration Statement and related prospectuses, (ii) the Company’s Amended and Restated Certificate of Incorporation, as amended, and Amended and Restated Bylaws, each as currently in effect, (iii) the forms of the Company’s Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, each of which is to be in effect immediately following the closing of the Company’s initial public offering, in the forms filed as Exhibits 3.2 and 3.4, respectively, to the Company’s Registration Statement on Form S-1 (No. 333-263295), (iv) the Plans and (v) originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below.

We have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies, the accuracy, completeness and authenticity of certificates of public officials, and the due authorization, execution and delivery of all documents by all persons other than the Company where authorization, execution and delivery are prerequisites to the effectiveness thereof. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plans, the Registration Statement and related prospectuses, will be validly issued, fully paid, and nonassessable (except as to shares issued pursuant to certain deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

Cooley LLP 3175 Hanover Street Palo Alto, CA 94304-1130

t: (650) 843-5000 f: (650) 849-7400 cooley.com


Sincerely,

Cooley LLP

By:		/s/ Josh Seidenfeld
Josh Seidenfeld