Kathyleen A. O'Brien Photo

Kathyleen is a partner in the firm’s Los Angeles and Century City offices and is a member of the firm’s Regulatory Litigation, Intellectual Property, and Advertising, Entertainment, and Media Groups. Kathyleen has extensive experience litigating complex business matters, including class actions, with a particular emphasis on antitrust, franchise and distribution, intellectual property, advertising and unfair trade practices issues. Kathyleen also has represented clients in civil and criminal investigations by federal and state agencies. She has successfully defended clients in a wide range of industries including aerospace, batteries, billboards, chain link fences, computer games, consumer electronics, cosmetics and hair care products, entertainment and media, golf clubs, health care, Internet sales and distribution, mobile homes, retail sales, tires, toys and games, and trash hauling. 

Kathyleen also counsels clients on a broad range of antitrust issues and regularly conducts internal investigations and antitrust compliance programs. Areas of specialization include trade association and industry group issues, group purchasing and standard setting issues and a full range of marketing, sales and distribution issues including group boycotts, refusals to deal, customer allocation, tying arrangements, product pricing, discounting, and advertising support. She also has defended corporate clients against state franchise claims by terminated dealers.


  • Georgetown University Law Center, 1978, J.D., with honors

  • California
  • Massachusetts
  • New York

Notable Quotes

  • 22 August 2017 "Don't Discount Deceptive Pricing Class Actions" Bloomberg BNA