Brian J. O'Connor

Brian O'Connor

Brian O'Connor is co-chair of Venable's Transactional Tax Group. Brian provides sophisticated tax and business advice to publicly traded and closely held businesses and their owners. His practice focuses on foreign and domestic tax matters for partnerships, limited liability companies, joint ventures, both C and S corporations, real estate investment trusts (REITs), and regulated investment companies (RICs). He is also regularly consulted by wealthy individuals and entrepreneurs on federal and state income tax matters and federal estate and gift tax issues.

As a transactional tax attorney, Brian works on transactions ranging from small sales transactions to merger or acquisition transactions in the billions of dollars. Similarly, as a tax controversy attorney, he has represented both individual clients in small audit matters and publicly traded corporate clients in tax disputes with amounts at issue in excess of $1 billion.  

Before joining Venable, Brian was an attorney-advisor for the Office of Chief Counsel at the IRS, where he worked on high-profile legislative projects, regulations, and other published guidance related to partnerships, S corporations, trusts, common trust funds, and cooperatives.

His valuable experience and continuing connections with the government, when combined with his significant private practice experience, permit Brian to provide unique insights to his clients, both large and small, on important tax and business issues.


Government Experience

  • Attorney-Advisor, Internal Revenue Service, Office of Chief Counsel




  • LL.M. with distinction Georgetown University Law Center 1996
    • Shell Oil scholar (highest possible grade point average)
    • Thomas Bradbury Chetwood, S.J. Prize for the Most Distinguished Academic Performance Leading to a Master of Laws Degree in Taxation
  • J.D. magna cum laude Washington and Lee University School of Law 1991
    • Order of the Coif

Bar Admissions

  • Maryland
  • Virginia
  • District of Columbia

Court Admissions

  • U.S. Tax Court

Professional Memberships and Activities

  • Member, American Bar Association, Tax Section
  • Member, District of Columbia Bar, Tax Section
  • Member, Maryland Bar Association, Tax Section
  • Member, Virginia Bar Association, Tax Section
  • Adjunct professor, Graduate Tax Program, Georgetown University Law Center, where he teaches an advanced course focusing on the technical tax aspects of partnerships and practical matters, including preparation of partnership and limited liability company agreements


  • The Best Lawyers in America
    • Lawyer of the Year, Litigation and Controversy: Tax, Maryland, 2016, 2018, 2020, 2024
    • Lawyer of the Year, Tax Law, Baltimore, 2022
    • Litigation and Controversy: Tax and Tax Law, 2006 – 2024
  • Legal 500, Domestic Tax, East Coast
  • The Washington Post, Top Lawyers, Baltimore and Washington, DC
  • Tax Directors Handbook
  • Super Lawyers, Maryland
  • Who’s Who Legal, Corporate Tax (One of only two Maryland lawyers selected)
  • Best of the U.S., Best of Class, Tax Law
  • The Best Attorneys Network, Tax Law