GROUP 1 AUTOMOTIVE 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. )

Check the appropriate box:

Preliminary Proxy Statement

Confidential, for Use of the Commission only (as permitted by Rule 14a-6(e)(2))

Definitive Proxy Statement

Definitive Additional Materials

Soliciting Material under §240.14a-12

GROUP 1 AUTOMOTIVE, 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):

No fee required.

Fee paid previously with preliminary materials.

Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.

Our Core Values

Notice of 2026 AnnualMeeting of Shareholders

PLACEOur 2026 Annual Meeting will be held in a virtual-only format at:www.virtualshareholdermeeting.com/GPI2026DATE AND TIMEMay 12, 20269:00 a.m. Central Daylight TimeYour vote is very important. Please submit your proxy card or voting instruction form as soon as possible.

Who may voteIf you owned shares of Group 1 Automotive, Inc. (the “Company”, “Group 1”, or “GPI”) common stock at the close of business on March 18, 2026, you are entitled to receive this Notice of the 2026 Annual Meeting of Shareholders (the “2026 Annual Meeting”) and to vote at the meeting, either during the virtual meeting or by proxy.How to attendTo be admitted to the 2026 Annual Meeting, enter the 16-digit voting control number found on your proxy card, voting instruction form, or email notification. You can find detailed instructions on pages 74 -75 of this Proxy Statement.Please review this Proxy Statement and vote in one of the four ways shown to the right under “Voting Methods Available to You.”Houston, TexasApril 2, 2026By Order of the Board of DirectorsGillian A. HobsonSenior Vice President, Chief Legal Officer and Corporate Secretary

VOTING METHODS AVAILABLE TO YOU

InternetVisit the website shown on the proxy card (www.proxyvote.com), voting instruction form or electronic communications.

TelephoneCall the telephone number identified in your proxy card, voting instruction form or electronic communications.

MailSign, date and return your proxy card or voting instruction form in the enclosed envelope.

During the MeetingAttend the 2026 Annual Meeting online. See pages 74-75 for instructions on how to attend and vote online.

Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to be held on May 12, 2026. This Notice of the 2026 Annual Meeting of Shareholders and Proxy Statement, as well as the Company’s 2025 Annual Report, are available free of charge atwww.proxyvote.com. References in either document to our website are for the convenience of readers, and information available at or through our website is not a part of, nor is it incorporated by reference in, the Proxy Statement or the 2025 Annual Report.

The Board of Directors of Group 1 (the “Board”) is soliciting proxies to be voted at our 2026 Annual Meeting of Shareholders on May 12, 2026, and at any postponed or reconvened meeting. We expect that the proxy materials or a notice of internet availability will be mailed and made available to shareholders beginning on or about April 2, 2026. At the meeting, votes will be taken on the matters listed in the Notice of 2026 Annual Meeting of Shareholders.