Stephen Joel Barrett is an American retired psychiatrist, author, and consumer advocate best known for his work combatting health fraud and promoting evidence-based medicine. He founded Quackwatch, a network of websites that critiques unproven or questionable medical practices, and co-founded the National Council Against Health Fraud.

A longtime critic of pseudoscience and alternative medicine, Barrett has written extensively on medical misinformation and served as an advisor to several scientific and health advocacy organizations. His work has earned him both praise from scientific communities and criticism from proponents of alternative health practices.