Siobhan A. Cullen is an experienced litigator who has represented life science, healthcare, retail and other employers in complex and class action litigation. She has successfully defended lawsuits brought against clients in both state and federal courts in California and other jurisdictions in cases involving employment issues, commercial disputes, unfair competition, and product liability. Her practice also includes counseling clients on compliance issues and conducting investigations. Siobhan has specific experience managing litigation, crafting discovery strategy, and preparing and defending employees, management and expert witnesses at deposition and trial. Siobhan is a pragmatic counselor and litigator who works to understand her clients’ people, missions and business objectives.

Siobhan’s practice focuses on:

  • Litigation and trials
  • Class actions
  • Unfair competition and trade secrets
  • Discrimination and harassment practice 
  • Investigations         

Prior to joining Littler, Siobhan’s practice focused on complex and class action litigation involving both U.S. and multinational companies.

Affiliazioni professionali e istituzionali


Section of Litigation

American Bar Association

Past Member

Louis M. Welsh American Inn of Court

News, Analysis & Press

Civility in the Practice of Law

ABA Practice Points

May 22, 2018


  • J.D., University of San Diego School of Law, 1995
  • B.A., University of California, San Diego, 1991

Foro di appartenenza



  • U.S. District Court, Southern District of California
  • U.S. District Court, Central District of California
  • U.S. District Court, Northern District of California
  • Superior Court of California, County of Orange
  • Superior Court of California, County of San Diego
  • Superior Court of California, County of Los Angeles
  • Superior Court of California, County of San Francisco