William Bronston (born March 1939) is an American physician and activist known for his involvement in the deinstitutionalization of Willowbrook State School in the early 1970s. Born in Los Angeles, Bronston graduated from the University of California, Los Angeles and the USC School of Medicine. At USC, he was a prominent student activist, organizing social and political public health projects and co-founding the New Left Student Health Organization. After graduating from USC in 1965, Bronston began his residency at the Menninger School of Psychiatry in Kansas, but was expelled from the institution after leading a sit-in for improvements in wages and working conditions for direct support professionals.

After his expulsion in 1968, Bronston moved to New York City where he briefly worked at a Black Panther Party medical clinic before leaving to become a staff physician at Willowbrook State School, a state institution for children with intellectual disabilities. At Willowbrook, Bronston quickly became critical of the institution's leadership and standards, clashing with Jack Hammond, the institute's director. In 1971, Bronston went public with his grievances and organized a movement to reform the institution, which culminated in a 1975 court decision deinstitutionalizing the school. Afterwards, Bronston returned to California, where he became the medical director of the Department of Developmental Disabilities at the California Department of Health and later at the California Department of Rehabilitation.

William Bronston was born in March 1939 to Bessarabian-born Jewish American film producer Samuel Bronston (1908–1994) and Ukrainian American pianist Sara "Dony" Bronston (1911–1990). Bronston was born in Los Angeles and raised in an affluent family in Beverly Hills, California. He is the great-nephew to Russian Marxist revolutionary Leon Trotsky. Bronston has one younger sister, as well as four other half or step-siblings. Bronston's parents divorced when he was thirteen and he stayed with his mother with his sister moved in with his father.

Bronston attended West Hollywood Elementary School, Bancroft Junior High School, and Hollywood High School. At sixteen, Bronston enrolled at the University of California, Los Angeles (UCLA), as a pre-med major. Influenced by art history classes he took at UCLA, Bronston switched majors to 20th-century history while also continuing his pre-med studies. At twenty, Bronston married his first wife Janet, a flight attendant for Trans World Airlines (TWA), whom he had met two years earlier. After being rejected from a number of medical schools, Bronston spent a fifth year at UCLA, graduating in 1961 with a Bachelor of Arts in contemporary history with a minor in contemporary art history.

After graduating from UCLA, Bronston attended the USC School of Medicine. In his first year, Bronston completed a fellowship in pediatrics at the Child Therapy Clinic at the Children's Hospital Los Angeles under Richard Koch [Wikidata], a professor of pediatrics at USC. In September 1964, when Bronston was a senior, he helped organize the USC Medical Student Forum with sophomore Michael McGarvey and advice from former members of the Association of Internes and Medical Students (AIMS). The USC Medical Student Forum was a series of lecture forums featuring a number of influential figures covering a variety of topics in medicine. These included a forum on the legalization of abortion with Planned Parenthood president Alan Guttmacher, a forum on the health effects of Jim Crow laws with civil rights activist H. Jack Geiger and others with Michael Harrington, Thomas Szasz and Benjamin Spock.

Inspired by the success of the forum, Bronston and McGarvey also began the student newspaper Borborygmi (meaning "stomach rumbles") in 1964, which featured essays and editorials centering on medical students. In January 1965, the two transformed the lecture forums into the Student Medical Action Conference (SMAC), which integrated the forums with praxis by organizing various social and political public health projects. After graduating from USC in spring 1965, Bronston flew across the country to coordinate a national students movement in the health sciences, aided by his access to discounted flights from his wife's job at TWA.

In October 1965, Bronston organized a national convention at the University of Chicago, where Bronston co-founded the Student Health Organization (SHO). The SHO, whose name was based on the World Health Organization, was a product of the New Left and imagined a national organization of medical students similar to the Students for a Democratic Society (SDS) and the Student Nonviolent Coordinating Committee (SNCC).

During his senior year of medical school, Bronston toured various post-doctoral programs in Sweden for intellectually disabled children but was unable to attend because the draft board prohibited him traveling abroad. In 1965, Bronston chose to attend the residency program at the Menninger School of Psychiatry at Topeka State Hospital in Kansas. Bronston's first wife Janet did not want to move to Kansas and the two separated that year. At Topeka, Bronston led the predominantly African American direct support professionals in re-activating the dormant health workers' union and organizing a sit-in for improvements in wages and working conditions, which led to his expulsion from the institution in June 1968.