Filed Pursuant to Rule 424(b)(3)
Registration Statement No. 333-253175

PROSPECTUS SUPPLEMENT NO. 6

(To prospectus dated May 12, 2021)

Up to 29,368,920 Shares of Common Stock

This prospectus supplement no. 6 amends and supplements the prospectus dated May 12, 2021, relating to the offering and resale by the selling stockholders identified in the prospectus of up to 29,368,920 shares of our common stock, par value $0.0001 per share (as supplemented or amended from time to time, the “Prospectus”).

This prospectus supplement incorporates into the Prospectus the information contained in our attached current report on Form 8-K, which was filed with the Securities and Exchange Commission on October 1, 2021.

You should read this prospectus supplement in conjunction with the Prospectus, including any supplements and amendments thereto. This prospectus supplement is qualified by reference to the Prospectus except to the extent that the information in the prospectus supplement supersedes the information contained in the Prospectus.

This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the Prospectus, including any supplements and amendments thereto.

Our common stock is listed on the NASDAQ Global Market under the symbol “GMTX.” On September 30, 2021, the last reported sale price of our common stock on the NASDAQ Global Market was $4.04.

Investment in our common stock involves risks. See “Risk Factors” beginning on page 10 of the Prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is October 1, 2021.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): September 29, 2021

GEMINI THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

(617) 401-4400

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

☒     Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

☐    If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

On September 29, 2021, Gemini Therapeutics, Inc. (the “Company”) held its 2021 Annual Meeting of Stockholders (the “2021 Annual Meeting”). Proxies were solicited pursuant to the Company’s proxy statement filed on August 17, 2021 with the Securities and Exchange Commission under Section 14(a) of the Securities Exchange Act of 1934, as amended. As of August 2, 2021, the record date for the 2021 Annual Meeting, there were 43,055,112 shares of the Company’s common stock, par value $0.0001 per share, (the “Common Stock”) outstanding and entitled to vote at the 2021 Annual Meeting. A total of 28,632,671 shares of Common Stock were present or represented by proxy at the 2021 Annual Meeting, representing 66.50% of the issued and outstanding shares entitled to vote at the meeting, representing a quorum. Each share of Common Stock was entitled to one vote with respect to matters submitted to the Company’s stockholders at the 2021 Annual Meeting. The proposals voted upon and the final results of the vote were as follows:

Proposal No. 1: Election of Class I Director. Carl L. Gordon was duly elected to the Company’s Board as a Class I director. The results were as follows:

Proposal No. 2: Approval of the Company’s 2021 Employee Stock Purchase Plan. The Company’s 2021 Employee Stock Purchase Plan was approved. The results were as follows:

Proposal No. 3: Ratification of Independent Registered Public Accounting Firm. The appointment of Ernst &Young as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2021 was ratified. The results were as follows:

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Dated: October 1, 2021