American Academy of Forensic Sciences (AAFS): A professional society dedicated to advancing forensic science and its application to the legal system. AAFS provides networking opportunities, educational resources, and hosts an annual scientific meeting.

American Board of Forensic Psychology (ABFP): An organization that certifies psychologists as forensic experts. It promotes the application of psychology to legal issues and maintains a directory of certified experts.

American Psychological Association (APA) - Division 41 (American Psychology-Law Society): This division of the APA focuses on the intersection of psychology and the legal system. It offers resources for psychologists working as expert witnesses or in other legal settings.

American Bar Association (ABA) - Section of Litigation: While not specifically for expert witnesses, this section of the ABA provides valuable insights into the legal profession and litigation process, which can be useful for expert witnesses to understand the legal landscape better.

National Association of Forensic Economics (NAFE): An organization for economists and other professionals involved in forensic economics. It offers training, publications, and networking opportunities.

National Association of Certified Valuators and Analysts (NACVA): This association focuses on business valuation, financial litigation, and expert witness services. It provides certification programs and resources for professionals in these fields.

The Expert Witness Institute (EWI): Based in the United Kingdom, EWI is an organization that supports and promotes expert witnesses across various disciplines. It offers training, guidance, and a directory of experts.

The Academy of Experts (TAE): Another UK-based organization, TAE, provides accreditation and training for expert witnesses. It also offers resources and a code of conduct for its members.