ProMIS Neurosciences Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14 (a) of the

Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant☒ Filed by a party other than the Registrant☐

Check the appropriate box:

PROMIS NEUROSCIENCES INC.

(Name of Registrant as Specified in its Charter)

Not applicable.

(Name of Person (s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

PROMIS NEUROSCIENCES INC.

SUITE 200, 1920 YONGE STREET

TORONTO, ONTARIO, CANADA M4S 3E2

(416) 847-6898

NOTICE OF 2026 ANNUAL MEETING OF

SHAREHOLDERS

To Be Held on May 20, 2026

To Our Shareholders:

You are cordially invited to attend the 2026 Annual Meeting of Shareholders (the “Annual Meeting”) of ProMIS Neurosciences Inc. (the “Company”). This year’s Annual Meeting will be a virtual meeting, which will be conducted via live webcast on Wednesday, May 20, 2026 at 10:30 a.m., Eastern Time. You may attend the meeting virtually by registering at http://www.virtualshareholdermeeting.com/PMN2026, where you will be able to vote electronically and submit questions, subject to the registration procedures set forth below.

Only shareholders who owned our common shares, no par value (“Common Shares”) at the close of business on March 23, 2026 can vote at the Annual Meeting or any adjournment that may take place. At the Annual Meeting, the shareholders will consider and vote on the following matters:

In addition, at our Annual Meeting, the shareholders will receive (but not vote on) the consolidated financial statements of the Company for the fiscal year ended December 31, 2025, including the auditor’s report therein.

As noted above, our Annual Meeting will be a “virtual meeting” of shareholders, which will be conducted exclusively via the Internet. There will not be a physical meeting location, and shareholders will not be able to attend the Annual Meeting in person. You may attend the Annual Meeting via the Internet, vote your shares during the Annual Meeting, and submit questions before the Annual Meeting by registering athttp://www.virtualshareholdermeeting.com/PMN2026.

In order to attend the meeting online, vote your shares electronically during the meeting and submit questions before the meeting, registered shareholders must register in advance athttp://www.virtualshareholdermeeting.com/PMN2026 using the control number located in the box in the upper right-hand corner of your proxy card or in the body of the e-mail notification you received. Most of our shareholders do not hold shares directly in their own name but instead are non-registered shareholders who beneficially own shares that are held by an intermediary, such as their bank, trust company, securities broker, trustee, or other nominee. If you are a non-registered shareholder and wish to attend the meeting online, vote your shares electronically during the meeting and submit questions before the meeting, you must appoint yourself as your proxyholder following the procedures provided to you by your intermediary and register in advance at http://www.virtualshareholdermeeting.com/PMN2026. Upon completing your registration, you will receive further instructions via email, including your unique links that will allow you to access the meeting and will permit you to submit questions. Further information about how to attend the Annual Meeting online, vote your shares and submit questions is included in the accompanying proxy statement.

You can find more information, including the nominees for director, in the proxy statement for the Annual Meeting, which is attached and also available for viewing, printing and downloading at www.proxyvote.com. As outlined in the

attached proxy statement, the board of directors recommends that you vote in favor of each director nominee in Proposal 1 and in favor of Proposals 2 and 3.

Instead of mailing a paper copy of our proxy materials to all of our shareholders, we are providing access to our proxy materials via the Internet under Canadian and U.S. securities laws. As a result, we are sending to our shareholders a Notice of Internet Availability of Proxy Materials (the “Notice”), instead of a paper copy of this proxy statement and our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (the “2025 Annual Report”). This Notice is dated April 10, 2026 and we plan to mail the Notice on or about April 10, 2026. The Notice contains instructions on how to access our proxy materials over the Internet. The Notice also contains instructions on how each of our shareholders can receive a paper copy of our proxy materials, including the proxy statement, our 2025 Annual Report, and a form of proxy card.

Shareholders of record at the close of business on March 23, 2026, the record date for the Annual Meeting, are entitled to notice of, and to vote at, the Annual Meeting or any adjournment or postponement of the Annual Meeting. A complete list of registered shareholders will be available to shareholders of record during the Annual Meeting.

Your vote is very important, regardless of the number of shares you own. Whether or not you expect to attend the Annual Meeting, please vote your shares by proxy in advance of the Annual Meeting to ensure your representation and the presence of a quorum at the Annual Meeting. To ensure that your vote is recorded promptly, please vote as soon as possible, even if you plan to attend the Annual Meeting.

If you are a shareholder of record, you may vote your shares by proxy in advance of the Annual Meeting on the Internet by visitingwww.proxyvote.com, by telephone by calling 1-800-690-6903 and following the recorded instructions or by completing, signing, dating, and returning a proxy card. If you mail your proxy card or vote by telephone or the Internet and then decide to vote your shares online during the Annual Meeting, you may still do so provided you register in advance athttp://www.virtualshareholdermeeting.com/PMN2026. Your proxy is revocable in accordance with the procedures set forth in the proxy statement.

If you are a non-registered shareholder, you will receive instructions from the holder of record that you must follow in order to vote your shares by proxy in advance of the Annual Meeting.

Thank you for your ongoing support and continued interest in ProMIS Neurosciences Inc.

The content and sending of the proxy statement has been authorized by order of the Board of Directors,

Neil K. Warma

Chief Executive Officer

Toronto, Ontario

April 10, 2026