Terrence Vance "Terry" Gilliam (pronounced /ˈɡɪliəm/) (born 22 November 1940) is an American-born British writer, filmmaker, animator, actor and member of the Monty Python comedy troupe. Gilliam is also known for directing several well-regarded films including Time Bandits (1981), Brazil (1985), The Fisher King (1991), and 12 Monkeys (1995). He is the only "Python" not born in Britain, but gained British citizenship in 1968.

Gilliam was born in Medicine Lake, Minnesota, the son of Beatrice (née Vance) and James Hall Gilliam, who was a traveling salesman for Folgers before becoming a carpenter. Gilliam has two siblings: a sister two years younger, and a brother ten years younger.

The family moved to Panorama City, California, in 1952 because of his sister's bout of pneumonia. Gilliam attended Birmingham High School where he was class president, senior Prom King, was voted "Most Likely to Succeed", and got straight A's. During high school, he discovered Mad magazine, which was then edited by Harvey Kurtzman; this later influenced his work.