Cynthia Castillo litigates high-stakes, complex civil cases with a focus on contractual disputes and consumer class actions, particularly Telephone Consumer Protection Act (TCPA) class actions.

She has represented a broad range of clients, including private equity firms, cannabis companies, large technology companies, startups, nonprofits, and individuals. While she typically handles business disputes and consumer claims, her broad litigation background includes experience with matters such as environmental liability, governmental enforcement actions, and bankruptcy claims. The breadth of her litigation experience allows her to quickly spot risks and develop creative solutions for her clients. 

Cynthia has experience preparing for and taking cases to trial. She successfully defended a private equity management firm at trial in an employment and breach of contract suit brought by one of its former officers. She has also prosecuted and tried to verdict a number of criminal cases as a “loaner” Deputy District Attorney in the Contra Costa County District Attorney’s Office.

Cynthia is active in the community. She is a member of the board of directors for the San Francisco La Raza Lawyers Association. As a board member, she co-founded the Latina Committee, which serves as a network for Latina lawyers practicing in the Bay Area. She also regularly mentors young lawyers, law students, and prospective law students. She is a past member of the Edward J. McFetridge Inn of Court.  She also maintains an active pro bono practice, which has included assisting a victim of domestic violence from Honduras to obtain asylum in the United States.

Cynthia served as a law clerk for the Honorable Philip Martinez of the United States District Court for the Western District of Texas. Before attending law school, she taught 4th and 6th grade with Teach for America.


  • Best Lawyers in America: Ones to Watch, Commercial Litigation (2024)
  • Leadership Council on Legal Diversity (LCLD) Pathfinders (Class of 2022)

Memberships and Affiliations

  • Member, Executive Committee, Litigation Section, Barristers Club of the Bar Association of San Francisco
  • Member, Edward J. McFetridge American Inn of Court (2021)
  • Board of Directors, San Francisco La Raza Lawyers Association; co-chair Latina Committee, which serves as a network for Latina lawyers practicing in the Bay Area.