Additional Proxy Soliciting Materials (Form DEFA14A)

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:

Gran Tierra Energy Inc.

(Name of Registrant as Specified In Its Charter)

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

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

Your Vote Counts! GRAN TIERRA ENERGY INC. 2026 Annual Meeting Vote by May 06, 2026 11:59 PM ET You invested in GRAN TIERRA ENERGY INC. and it's time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the shareholder meeting to be held on May 08, 2026. Get informed before you vote View the Annual Report, Notice & Proxy Statement online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 26, 2026. If you would like to request a copy of the material(s) for this and/or future shareholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to [email protected]. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. For complete information and to vote, visit www.ProxyVote.com Control # Smartphone users Vote in Person at the Meeting* Point your camera here and May 08, 2026 vote without entering a 10:00 AM MDT control number Virtual Meeting https://meetings.lumiconnect.com/400-401-359-207 *If you choose to vote these shares in person at the meeting, you must request a "legal proxy." To do so, please follow the instructions at www.ProxyVote.com or request a paper copy of the materials, which will contain the appropriate instructions. Please check the meeting materials for any special requirements for meeting attendance.

Vote at www.ProxyVote.com THIS IS NOT A VOTABLE BALLOT GRAN TIERRA ENERGY INC. This is an overview of the proposals being presented at the 2026 Annual Meeting Vote by May 06, 2026 upcoming shareholder meeting. Please follow the instructions on 11:59 PM ET the reverse side to vote these important matters. Voting Items Board Recommends 1. Election of Directors Nominees: 1A Gary S. Guidry For 1B Robert B. Hodgins For 1C Alison Redford For 1D Ronald W. Royal For 1E Brooke Wade For 2 Proposal to ratify the appointment of KPMG LLP as Gran Tierra Energy Inc.'s independent registered public For accounting firm for Fiscal Year 2026. 3 Proposal to approve, on an advisory basis, the compensation of Gran Tierra Energy Inc.'s named executive officers, For as disclosed in the proxy statement. NOTE: Such other business as may properly come before the meeting or any adjournment thereof. Under New York Stock Exchange rules, brokers may vote "routine" matters at their discretion if your voting instructions are not communicated to us at least 10 days before the meeting. We will nevertheless follow your instructions, even if the broker's discretionary vote has already been given, provided your instructions are received prior to the meeting date.