Nancy Lesser

Treaty or Agreement

Contact Information:


2101 L Street, NW, Suite 800
Washington, DC 20037

Phone: (202) 775-8100
Fax: (202) 318-0203



Nancy Lesser is the principal of Pax ADR LLC, a dispute resolution firm headquartered in Washington, D.C.  Ms. Lesser brings to her mediation and arbitration practice skills honed over twenty years of service as a neutral. Prior to establishing her own firm, she was a partner with the distinguished law firm of Williams & Connolly, where she specialized in complex commercial cases.

Ms. Lesser has handled hundreds of challenging disputes as a mediator and arbitrator.  She was named one of the  "Alternative Dispute Resolution Champions" in 2016 and 2017 by the National Law Journal. The Washington Legal Times named her “Best Individual Mediator” and she is consistently listed as one of Washingtonian Magazine's "Best Mediators."

Ms. Lesser serves on the Large, Complex Commercial Disputes Arbitration Panel of the American Arbitration Association, the Panel of Neutrals for the American Health Lawyers Association,  and the Panel of Distinguished Neutrals for the Commercial, Banking, Accounting and Financial Services, and Real Estate Panels of the CPR Institute for Dispute Resolution. She is a Fellow of the College of Commercial Arbitrators.

 Ms. Lesser works with Fortune 500 companies, federal and state agencies, small businesses, and individuals. She also conducts independent fact-finding and internal investigations. Her clients face critical and complex problems, ranging from:

  • government and private contract claims

  • insurance coverage disputes

  • whistleblower claims, including False Claims Act and Sarbanes Oxley actions

  • securities cases, including FINRA proceedings and SEC enforcement actions

  • intellectual property claims, including patent, copyright and software licensing issues

  • securities and consumer class actions and shareholder suits

  • personal injury claims, including medical, legal and accounting malpractice actions

Parties look to Ms. Lesser for an efficient process to resolve their disputes without incurring the expense, frustration, and delay of traditional litigation.


Ms. Lesser has handled a wide variety of commercial arbitrations involving multi-million dollar claims. She has served as chair of a number of panels and has also served as sole arbitrator in other matters. Ms. Lesser has a broad range of arbitration experience, from contract and securities cases to intellectual property disputes and insurance coverage claims. She has presided over a number of utility ratemaking cases; an audit of alleged overcharges by an electrical utility to a major municipality; accounting disputes regarding post-acquisition closing balance sheets; breach of contract and breach of fiduciary duty claims between joint venture partners; breach of contract actions between suppliers and customers for services or goods; and data compensation proceedings under the Federal Insecticide, Fungicide, and Rodenticide Act. She serves as Standing Chair of the National Arbitration Panel, hearing disputes between Amtrak and the freight railroads. For more details about Ms. Lesser’s experience, see practice areas.


Ms. Lesser has been helping parties resolve seemingly intractable disputes for almost twenty years. She has mediated hundreds of complex business claims, in cases as diverse as an accounting dispute between the City of New Orleans and an electrical utility; a 20-year class action between a federal employee union and the United States; False Claims Act qui tam actions and Sarbanes Oxley whistleblower cases; a host of breach of contract suits; wrongful death and personal injury claims against the District of Columbia; trademark and patent disputes involving industries as diverse as lighting, food products, medical devices, sound systems and software. For more details about Ms. Lesser’s experience, see practice areas.


  • Chair of the Amtrak National Arbitration Panel, which hears disputes between Amtrak and the freight railroads nationwide.

  • Large Complex Case Arbitrator and Master Mediator, American Arbitration Association.

  • Panel of Distinguished Neutrals for the Commercial and Banking, Accounting and Financial Services Panels of the CPR Institute for Dispute Resolution.

  • Member, National Academy of Distinguished Neutrals.

  • Mediation panels, U.S. District Court for the District of Columbia, the U.S. Court of Appeals for the District of Columbia Circuit, and the U.S. Bankruptcy Court for the District of Maryland.


Ms. Lesser is a Fellow of the College of Commercial Arbitrators. She was past chair of the Ethical Guidance Committee of the Section of Dispute Resolution of the American Bar Association. She serves as mediation trainer for the U.S. Department of Justice, the International Trademark Association, and the International Law Institute. She speaks frequently on panels and to private groups. Ms. Lesser has served as an adjunct professor at the Georgetown University Law Center, teaching seminars on alternative dispute resolution and negotiation.


Founder and Principal, PAX ADR LLC, Washington, DC 2001-present

Alternative dispute resolution firm providing arbitration, mediation, and internal investigation services.

Senior Counsel to the Secretary, U.S. Department of Housing and Urban Development, Washington, DC 2000-2001

Legal advisor to Secretary; spearheaded major Secretarial policy initiatives, including fair housing enforcement, predatory lending, subsidized housing, historic preservation and community development.

Partner, Williams & Connolly, Washington, DC 1990-2000 (associate, 1982-1990)

Nationwide trial and appellate practice focusing on complex cases in federal and state courts. Cases handled included securities fraud class actions, corporate governance disputes, employment cases, intellectual property claims, and medical, legal and accounting malpractice claims. Conducted internal investigations involving banking fraud and securities violations. Served on Executive Committee of the firm from 1996-2000; chair of firm’s Diversity Committee from 1994-1996.

Associate, Cravath, Swaine & Moore, New York, NY 1981-1982

Litigation associate


J.D., Georgetown University Law Center, 1981, magna cum laude  
M.A., Urban and Environmental Planning, University of Virginia, 2000
B.A., City College of the City of New York, 1975, summa cum laude


2101 L Street, N.W., Suite 800
Washington, DC 20006

Phone: (202) 775-8100
Fax: (202) 318-0203