Document

Exhibit 5.1

June 14, 2024

Curis, Inc.

128 Spring Street, Building C – Suite 500

Lexington, MA 02421

Re: Fifth Amended and Restated 2010 Stock Incentive Plan

Amended and Restated 2010 Employee Stock Purchase Plan, as amended

Inducement Stock Option Award (April 1, 2024)

Ladies and Gentlemen:

We have assisted in the preparation of a Registration Statement on Form S-8 (the “Registration Statement”) to be filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), relating to (i) an aggregate of 1,342,100 shares of common stock, $0.01 par value per share (the “Common Stock”), of Curis, Inc., a Delaware corporation (the “Company”), issuable under the Company’s Fifth Amended and Restated 2010 Stock Incentive Plan and the Company’s Amended and Restated 2010 Employee Stock Purchase Plan, as amended (collectively, the “Plans,” and such shares of Common Stock, the “Plan Shares”) and (ii) an aggregate of 8,550 shares of Common Stock issuable pursuant to a nonstatutory stock option agreement providing for an employee inducement grant between the Company and an employee, which was entered into in connection with the commencement of such employee’s employment with the Company pursuant to Nasdaq Listing Rule 5635(c)(4) (the “Inducement Award Agreement”) (such shares of Common Stock, the “Inducement Award Shares” and, together with the Plan Shares, the “Shares”).

We have examined the Certificate of Incorporation and By-laws of the Company, each as amended and restated and/or amended to date, and originals, or copies certified to our satisfaction, of all pertinent records of the meetings of the board of directors and stockholders of the Company, the Registration Statement, the Plans, the Inducement Award Agreement, a certificate of a representative of the Company and such other documents relating to the Company as we have deemed material for the purposes of this opinion.

In our examination of the foregoing documents, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as certified, photostatic or other copies, the authenticity of the originals of any such documents and the legal competence of all signatories to such documents.

We assume that the appropriate action will be taken, prior to the offer and sale of the Shares in accordance with the Plans or the Inducement Award Agreement, as applicable, to register and qualify the Shares for sale under all applicable state securities or “blue sky” laws.

We express no opinion herein as to the laws of any state or jurisdiction other than the General Corporation Law of the State of Delaware.

It is understood that this opinion is to be used only in connection with the offer and sale of the Shares while the Registration Statement is in effect.

Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters.

Based on the foregoing, we are of the opinion that the Shares have been duly authorized for issuance and, when the Shares are issued and paid for in accordance with the terms and conditions of the Plans or the Inducement Award Agreement, as applicable, the Shares will be validly issued, fully paid and nonassessable.



Very truly yours, /s/ Wilmer Cutler Pickering Hale and Dorr LLP WILMER CUTLER PICKERING HALE AND DORR LLP