Hal Ashby (September 2, 1929 – December 27, 1988) was an American film director and editor associated with the "New Hollywood" wave. Before his directing career, Ashby edited films for Norman Jewison, in particular The Russians Are Coming, the Russians Are Coming! (1966), for which he received an Academy Award nomination for Best Film Editing, and In the Heat of the Night (1967), for which he won the Academy Award in the same category.

Ashby received a third Academy Award nomination, this time for Best Director, for Coming Home (1978). Other films directed by Ashby include The Landlord (1970), Harold and Maude (1971), The Last Detail (1973), Shampoo (1975), Bound for Glory (1976), and Being There (1979).

Born William Hal Ashby in Ogden, Utah, he was raised in a Mormon family. His turbulent childhood in a dysfunctional family included his parents' divorce, his father's suicide, and dropping out of high school. Ashby was married and divorced by the age of 19.

Entering adulthood, Ashby moved from Utah to California, where he soon became an assistant editor. After an Academy Award nomination for editing in 1967 for The Russians Are Coming, the Russians Are Coming!, his big break came in 1968 when he won the award for In the Heat of the Night. At the urging of producer Norman Jewison, Ashby directed his first film, The Landlord, in 1970. Although his birth date placed him squarely in the prewar generation, the director quickly embraced the hippie lifestyle, adopting vegetarianism and growing his hair long. In 1970, he married actress Joan Marshall. Although they remained married until his death in 1988, by the mid-seventies they had separated, and Marshall never forgave Ashby, as well as Warren Beatty and Robert Towne, for dramatizing some unflattering elements of her life in Shampoo.