Maze Therapeutics Inc — S-1 exhibit

Exhibit 5.1

October 17, 2025

Maze Therapeutics, Inc.

171 Oyster Point Blvd., Suite 300

South San Francisco, California 94080

Re: Registration Statement on Form S-1

Ladies and Gentlemen:

As counsel to Maze Therapeutics, Inc., a Delaware corporation (the “Company”), we have examined the Registration Statement on Form S-1 filed by the Company with the Securities and Exchange Commission (the “Commission”) on or about October 17, 2025 (the “Registration Statement”), including a related prospectus included in the Registration Statement (the “Prospectus”), in connection with the registration under the Securities Act of 1933, as amended (the “Securities Act”), of the offering and sale from time to time by the selling stockholders named in the Registration Statement (the “Selling Stockholders”) of up to 9,231,092 shares of the Company’s common stock $0.001 par value per share (the “common stock”), consisting of (a) 4,000,002 shares of common stock (the “Initial Shares”) and (b) up to 5,231,090 shares of common stock (the “Warrant Shares”, and together with the Initial Shares, the “Shares”) issuable upon the exercise of pre-funded warrants (the “Pre-Funded Warrants”) held by certain of the Selling Stockholders. This letter is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or related Prospectus, other than as expressly stated herein with respect to the issue of the Shares.

As to matters of fact relevant to the opinions rendered herein, we have examined such documents, certificates and other instruments which we have deemed necessary or advisable, including a certificate addressed to us and dated the date hereof executed by the Company. We have not undertaken any independent investigation to verify the accuracy of any such information, representations or warranties or to determine the existence or absence of any fact, and no inference as to our knowledge of the existence or absence of any fact should be drawn from our representation of the Company or the rendering of the opinions set forth below. We have not considered parol evidence in connection with any of the agreements or instruments reviewed by us in connection with this letter.

In our examination of documents for purposes of this letter, we have assumed, and express no opinion as to, the genuineness and authenticity of all signatures on original documents, the authenticity and completeness of all documents submitted to us as originals, that each document is what it purports to be, the conformity to originals of all documents submitted to us as copies or facsimile copies, the absence of any termination, modification or waiver of or amendment to any document reviewed by us (other than as has been disclosed to us), the legal competence or capacity

Maze Therapeutics, Inc.

October 17, 2025

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of all persons or entities (other than the Company) executing the same and (other than the Company) the due authorization, execution and delivery of all documents by each party thereto. We have also assumed the conformity of the documents filed with the Commission via the Electronic Data Gathering, Analysis and Retrieval System (“EDGAR”), except for required EDGAR formatting changes, to physical copies submitted for our examination.

The opinions in this letter are limited to the existing General Corporation Law of the State of Delaware now in effect. We express no opinion with respect to any other laws.

In connection with our opinion expressed below, we have assumed that, (i) the Registration Statement and any amendments (including any necessary post-effective amendments) will have been declared effective under the Securities Act and at the time of the offer, issuance and sale of the Shares, no stop order suspecting the Registration Statement’s effectiveness will have been issued and remain in effect, (ii) the Registration Statement will apply to the offer and sale of the Shares and will not have been modified or rescinded, (iii) no future amendments will be made to the Company’s current certificate of incorporation, as amended from time to time, or to the Company’s bylaws that would be in conflict or inconsistent with the Company’s right and ability to issue the Warrant Shares, (iv) at the time of the issuance and sale of the Warrant Shares, the Company will be validly existing as a corporation and in good standing under the laws of the State of Delaware, and (v) at the time of each exercise of the Pre-Funded Warrants, the Company will have a sufficient number of authorized and unissued shares of common stock available for issuance under the Company’s current certificate of incorporation, as amended from time to time, to permit full exercise of each of the Pre-Funded Warrants in accordance with their terms without the breach or violation of any other agreement, commitment or obligation of the Company.

Based upon the foregoing, and subject to the qualifications and exceptions contained herein, we are of the opinion that (i) the Initial Shares to be sold by the Selling Stockholders pursuant to the Registration Statement and the Prospectus are validly issued, fully paid and nonassessable and (ii) the Warrant Shares, when issued upon the exercise of the Pre-Funded Warrants in accordance with the terms thereof and delivered in the manner stated in the Registration Statement and the Prospectus, will be validly issued, nonassessable and fully paid.

We consent to the use of this opinion as an exhibit to the Registration Statement and further consent to all references to us, if any, in the Registration Statement, the Prospectus and any amendments thereto. In giving this consent we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission thereunder.

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Maze Therapeutics, Inc.

October 17, 2025

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This opinion is intended solely for use in connection with the sale of the Shares by the Selling Stockholders pursuant to the Registration Statement and is not to be relied upon for any other purpose. In providing this letter, we are opining only as to the specific legal issues expressly set forth above, and no opinion shall be inferred as to any other matter or matters. This opinion is rendered on, and speaks only as of, the date of this letter first written above, is based solely on our understanding of facts in existence as of such date after the aforementioned examination and does not address any potential changes in facts, circumstance or law that may occur after the date of this opinion letter. We assume no obligation to advise you of any fact, circumstance, event or change in the law or the facts that may hereafter be brought to our attention, whether or not such occurrence would affect or modify any of the opinions expressed herein.