Allogene Therapeutics, 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:

(Name of Registrant as Specified In Its Charter)

N/A

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

Payment of Filing Fee (Check all boxes that apply)

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held on June 18, 2026

Dear Stockholder:

You are cordially invited to attend the 2026 Annual Meeting of Stockholders ("Annual Meeting") of Allogene Therapeutics, Inc., a Delaware corporation (the "Company"). The meeting will be held on June 18, 2026 at 8:00 a.m., Pacific Time. The Annual Meeting will be a completely virtual meeting of stockholders. You can attend the Annual Meeting by visiting www.virtualshareholdermeeting.com/ALLO2026 where you will be able to listen to the meeting live, submit questions and vote online. We are holding the Annual Meeting for the following purposes, as more fully described in the accompanying Proxy Statement:

1. To elect the Board of Directors’ three nominees for director named herein to hold office until the 2029 Annual Meeting of Stockholders.

2. To approve, on an advisory basis, the compensation of the Company’s named executive officers, as disclosed in the Proxy Statement accompanying this notice.

3. To approve, on an advisory basis, the preferred frequency of stockholder advisory votes on the compensation of the Company's named executive officers.

4. To approve an amendment to our Certificate of Incorporation to increase the number of authorized shares of common stock from 400,000,000 shares to 800,000,000 shares.

5. To ratify the selection by the Audit Committee of the Board of Directors of Ernst & Young LLP as the independent registered public accounting firm of the Company for its fiscal year ending December 31, 2026.

6. To conduct any other business properly brought before the meeting.

These items of business are more fully described in the Proxy Statement accompanying this notice.

The record date for the Annual Meeting is April 20, 2026. Only stockholders of record at the close of business on that date may vote at the meeting or any adjournment thereof.

BY ORDER OF THE BOARD OF DIRECTORS

Earl Douglas

Senior Vice President, General Counsel and Corporate Secretary

South San Francisco, California

April 30, 2026

YOUR VOTE IS IMPORTANT. You are cordially invited to attend the meeting online. Whether or not you plan to attend the Annual Meeting, we urge you to submit your vote via the internet, telephone or mail as soon as possible to ensure your shares are represented. For additional instructions on voting by telephone or the internet, please refer to your Notice of Internet Availability of Proxy Materials or proxy card that may be mailed to you. Returning the proxy does not deprive you of your right to attend the Annual Meeting and to vote your shares at the Annual Meeting.

Table of Contents

210 East Grand Avenue

South San Francisco, California 94080

PROXY STATEMENT FOR THE

2026 ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON

June 18, 2026

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