LANDSTAR SYSTEM INC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule

14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

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Check the appropriate box:

Landstar System, Inc.

(Name of Registrant as Specified in its Charter)

Not applicable.

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LETTER FROM OUR NON-EXECUTIVE CHAIRMAN OF THE BOARD

To the Stockholders of Landstar System, Inc.: On behalf of the entire Board of Directors of Landstar System, Inc., we are pleased to invite you to attend the Annual Meeting of Stockholders to be held on Tuesday, May 5, 2026, at 9:00 a.m. Eastern Time, in a virtual-only meeting format. A notice of meeting, a proxy card, the 2025 Annual Report on Form 10-K and a Proxy Statement containing information about the matters to be acted upon at the 2026 Annual Meeting are enclosed. We hope you will attend the meeting virtually or by proxy and encourage you to vote your shares prior to the Annual Meeting. We are proud of how our organization has navigated one of the most prolonged freight downturns in recent history while continuing to execute against our long-term strategy. Under the leadership of our Chief Executive Officer, Frank Lonegro, we remain focused on enhancing the Landstar business model, strengthening the Landstar brand, investing in strategic growth opportunities, and delivering value for our stockholders. Notably, Landstar has accelerated its development of artificial intelligence tools and technologies that have the potential to transform the freight transportation industry and reinforce Landstar’s strategic positioning for long-term stockholder value creation. Our dedication to good governance practices remains unwavering, with a specific emphasis in 2025 on stockholder engagement, executive compensation matters, and director succession efforts. Following our long-standing commitment to refreshment of the Board, we were delighted to appoint J. Barr Blanton and Melanie M. Hart to the Landstar System, Inc. Board in October of 2025. Blanton, a former partner in McKinsey & Company’s transformation and private equity practices and current Chief Executive Officer of Crosslake Technologies, brings valuable strategic insight to both the Board and management. Similarly, Hart’s experience as Chief Financial Officer of Pool Corporation (NASDAQ: POOL) contributes significant expertise to Board discussions on global supply chain dynamics amidst an evolving, often volatile, tariff and trade policy environment. We are also deeply grateful to Board member Anthony Orlando for his eleven years of highly commendable service to Landstar and wish him all the best in his retirement. We are excited for the future and remain confident in the strength of the Landstar model and our ability to create enduring value for our stockholders.

Sincerely,

Landstar System, Inc. | 13410 Sutton Park Drive S. | Jacksonville, Florida 32224

NOTICE OF ANNUAL MEETING

OF STOCKHOLDERS

To Be Held May 5, 2026

Agenda:

Only stockholders of record at the close of business on March 10, 2026 will be entitled to notice of, and to vote at, the meeting. A list of stockholders eligible to vote at the meeting will be available during business hours from April 24, 2026 to the date of the meeting at the Company’s corporate headquarters located at 13410 Sutton Park Drive South, Jacksonville, Florida 32224.

The platform for the virtual 2026 Annual Meeting includes functionality that provides validated stockholders the same meeting participation rights and opportunities they would have at anin-person meeting. Instructions to access andlog-in to the virtual Annual Meeting are provided below. Once admitted, stockholders may view reference materials, submit questions and vote their shares by following the instructions that will be available on the meeting website.

For admission to the 2026 Annual Meeting, stockholders may go to www.virtualshareholdermeeting.com/LSTR2026 and enter the 16-digit control number you received with your proxy materials. Online access to the 2026 Annual Meeting will open at 8:45 a.m., Eastern Time on the morning of the meeting to allow time for stockholders tolog-in prior to the start of the live audio webcast of the 2026 Annual Meeting at 9:00 a.m. Eastern Time. Persons who do not have a control number may attend as guests and will be able to hear the audio webcast but will not be able to utilize the question, voting or other functionality noted above. A recording of the webcast will be available at www.virtualshareholdermeeting.com/LSTR2026, approximately 24 hours after the conclusion of the meeting.

All stockholders are cordially invited to attend the 2026 Annual Meeting. Whether you expect to attend the meeting or not, your proxy vote is very important. To assure your representation at the 2026 Annual Meeting, the Company encourages you to vote in advance of the meeting by using one of the methods set forth below, whether or not you plan to access the virtual meeting.

By Order of the Board of Directors

MICHAEL K. KNELLER

Vice President, General Counsel and Secretary

Jacksonville, Florida

March 23, 2026

Important Notice Regarding the Availability of Proxy Materials for the Stockholder meeting to be held on May 5, 2026:

The proxy statement and annual report to security holders are available atwww.landstar.com andwww.proxyvote.com.

The proxy statement and annual report are available at: www.landstar.com and www.proxyvote.com We are furnishing our proxy materials to all of our stockholders over the Internet rather than in paper form. We believe that this deliveryprocess lowers the costs of printing and distributing our proxy materials and reduces our environmental impact, without impacting ourstockholders’ timely access to this important information. Accordingly, stockholders of record at the close of business on March 10, 2026will receive a Notice of Internet Availability of Proxy Materials (the “Notice of Internet Availability”) and may vote at the meeting.Such stockholders will also receive notice of any postponements or adjournments of the meeting.The Notice of Internet Availability is being distributed to stockholders on or about March 23, 2026.

LANDSTAR SYSTEM, INC. 13410 Sutton Park Drive South Jacksonville, Florida 32224

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON MAY 5, 2026

The proxy statement and annual report to stockholders are available at www.landstar.com and www.proxyvote.com

In accordance with rules and regulations adopted by the U.S. Securities and Exchange Commission (the “SEC”), we are pleased to provide access to our proxy materials over the Internet to all of our stockholders rather than in paper form. Accordingly, a Notice of Internet Availability of Proxy Materials (the “Notice of Internet Availability”) has been mailed to our stockholders on or about March 23, 2026. Stockholders will have the ability to access the proxy materials on the websites listed above, or to request a printed set of the proxy materials be sent to them by following the instructions in the Notice of Internet Availability.

The Notice of Internet Availability also provides instructions on how you may request that we send future proxy materials to you electronically bye-mail or in printed form by mail. If you choose to receive future proxy materials bye-mail, you will receive ane-mail next year with instructions containing a link to those materials and a link to the proxy voting site. Your election to receive proxy materials bye-mail or in printed form by mail will remain in effect until you terminate it. We encourage you to choose to receive future proxy materials bye-mail, which will allow us to provide you with the information you need in a more timely manner, will save us the cost of printing and mailing documents to you and will conserve natural resources.

2 Landstar System, Inc. 2026 Proxy Statement