Kathleen O'Neill


I focus on antitrust and competition law, and I advise our clients on all aspects of government merger review, antitrust investigations, litigation and compliance.

Kathy advises clients on all aspects of antitrust and competition law, after serving 15 years with the US Department of Justice Antitrust Division, most recently as senior director of investigations and litigation, the top career civil position in the Antitrust Division. In that role, Kathy oversaw all merger and civil conduct investigations and litigations across industries. She previously served as chief of the Transportation, Energy and Agriculture Section of the Antitrust Division, and earlier as a trial attorney in the Telecommunications and Media Section, among other positions.

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  • Tulane Law School
    JD, cum laude, 1998

  • University of Pennsylvania
    BA, English
    with distinction, 1994

Admissions & Credentials

New York


Not admitted to practice in District of Columbia

Supervised by licensed members of the DC Bar

Rankings & Accolades

    Women@Competition: 40 in their 40s Notable Women Competition Professionals in Europe, the Americas and Africa (2019)

    Global Competition Review: Women in Antitrust award (2016)

    DOJ Antitrust Division: Assistant Attorney General Award for outstanding contributions to enforcement matters (eight-time winner)