Filed Pursuant to Rule 424(b)(3)

Registration Statement No. 333-253175

PROSPECTUS SUPPLEMENT NO. 7

(To prospectus dated May 12, 2021)

Up to 29,368,920 Shares of Common Stock

This prospectus supplement no. 7 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 6, 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 October 5, 2021, the last reported sale price of our common stock on the NASDAQ Global Market was $3.81.

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 6, 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): October 4, 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.

Item 2.05 Costs Associated with Exit or Disposal Activities

On October 4, 2021, the Board of Directors (the “Board”) of Gemini Therapeutics, Inc. (the “Company”) approved a restructuring plan (the “Plan”) to prioritize assets and focus on initiating and executing GEM103’s resource-intensive pivotal trial in geographic atrophy, resulting in a reduction of the Company’s workforce by 11 positions with a majority of these employees’ separation from the business to occur by mid-October 2021 and the remaining affected employees transitioning by the end of 2021. As a result of the Plan, the Company expects to incur a pre-tax restructuring charge in the fourth quarter of 2021 within the range of $1.3 million to $1.6 million, which is expected to consist of employee severance and other restructuring related costs and expenses. As the Plan is implemented, the Company’s management will re-evaluate the estimated costs and expenses set forth above and may revise the estimated restructuring charge as appropriate, consistent with generally accepted accounting principles.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

On October 4, 2021, the Company’s Chief Medical Officer, Samuel Barone, M.D., entered into an agreement with the Company (the “Retention Agreement”) to modify his role and responsibilities. Upon effectiveness of the Retention Agreement, Dr. Barone will retain his title of Chief Medical Officer, however, he will no longer be primarily responsible for the Company’s regulatory and medical affairs. Such responsibilities will be assumed by Avner Ingerman, M.D., the Company’s Chief Development Officer, effective immediately. Under the Retention Agreement, Dr. Barone will continue to receive his current salary and benefits and vest in his equity awards, and is also eligible to receive a cash incentive of up to $100,000, in two installments, upon achievement of certain milestones specified in the Retention Agreement. The Retention Agreement also provides that Dr. Barone is eligible to receive a retention bonus equal to the sum of (i) nine months of his base salary and (ii) a pro rata portion of his target bonus for the calendar year in which the last day of his employment occurs, to be paid in calendar year 2022 on a date determined by the Company.

In addition, effective as of October 4, 2021, the Company has appointed Brian Piekos, the Company’s Chief Financial Officer, the additional title of Chief Business Officer, and Mr. Piekos has assumed additional leadership responsibilities for various functions including manufacturing, business development and investor relations. Mr. Piekos will continue to serve as the principal financial officer and principal accounting officer of the Company.

Finally, Georges Gemayel, Ph.D., will transition to serve as the Executive Chair of the Company’s Board. Dr. Gemayel has served as Chair of the Company’s Board since May 2021.

Item 7.01 Regulation FD Disclosure

On October 5, 2021, the Company issued a press release entitled “Gemini Therapeutics Announces Corporate Restructuring to Prioritize Late-Stage Clinical Development of GEM103 for Geographic Atrophy.”

The information in this Item 7.01, including Exhibit 99.1 to this Current Report on Form 8-K, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as expressly set forth by specific reference in such a filing.

Forward-Looking Statements

Certain statements in this Current Report on Form 8-K may constitute “forward-looking statements” for purposes of the federal securities laws. Our forward-looking statements include, but are not limited to, statements regarding our or our management team’s expectations, hopes, beliefs, intentions or strategies regarding the future, including those relating to the timing of and costs associated with our planned restructuring, and the benefits we expect to receive from the restructuring, the success, cost and timing of our product development activities and clinical trials, whether such data, when final, will be consistent with interim reported data, the timing or ability to commence future clinical trials, the potential attributes and benefits of our product candidates, including GEM103, the reliability of the interim or final results of studies relating to safety and possible adverse effects resulting from the administration of our product candidates, our ability to obtain and maintain regulatory approval for our product candidates, our projected cash runway and our ability to obtain funding for our operations when needed. Forward-looking statements include statements relating to our management team’s expectations, hopes, beliefs, intentions or strategies regarding the future. In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. The words “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “will,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting us will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors described under the heading “Risk Factors” in Gemini’s most recent Annual Report on Form 10-K filed with the SEC, as well as discussions of potential risks, uncertainties, and other important factors included in any of our future filings with the SEC. Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. Some of these risks and uncertainties may in the future be amplified by the ongoing COVID-19 pandemic and there may be additional risks that we consider immaterial, or which are unknown. It is not possible to predict or identify all such risks. Our forward-looking statements only speak as of the date they are made, and we do not undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

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 6, 2021