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. )

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¨	Soliciting Material Pursuant to §240.14a-12

CORPORATE OFFICE PROPERTIES TRUST

(Name of Registrant as Specified In Its Charter)

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Your Vote Counts! CORPORATE OFFICE PROPERTIES TRUST 2021 Annual Meeting Vote by May 12, 2021 11:59 PM ET. For shares held in a Plan, vote by May 10, 2021 11:59 PM ET.CORPORATE OFFICE PROPERTIES TRUST 6711 COLUMBIA GATEWAY DRIVE, SUITE 300 COLUMBIA, MD 21046D42851-P53520You invested in CORPORATE OFFICE PROPERTIES TRUST 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 13, 2021. Get informed before you vote View the Notice and Proxy Statement and Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 29, 2021. 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 sendmaterial@proxyvote.com. 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 Point your camera here and vote without entering a control numberVirtually at:Vote Virtually at the Meeting* May 13, 2021 9:30 AMwww.virtualshareholdermeeting.com/OFC2021*Please check the meeting materials for any special requirements for meeting attendance.V1

Vote at www.ProxyVote.comTHIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming shareholder meeting. Please follow the instructions on the reverse side to vote these important matters.Voting Items 1. Election of Trustees Nominees: 1a) Thomas F. Brady 1b) Stephen E. Budorick 1c) Robert L. Denton, Sr. 1d) Philip L. Hawkins 1e) David M. Jacobstein 1f) Steven D. Kesler 1g) Letitia A. Long 1h) Raymond L. Owens 1i) C. Taylor Pickett 1j) Lisa G. Trimberger 2. Ratification of the Appointment of Independent Registered Public Accounting Firm. 3. Approval, on an Advisory Basis, of Named Executive Officer Compensation. NOTE: Such other business as may properly come before the meeting or any adjournment thereof.Board RecommendsFor For For For For For For For For For For ForPrefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up for E-delivery”.D42852-P53520