Witness is a 1985 American thriller film released by Paramount Pictures, and starring Harrison Ford, Kelly McGillis and Lukas Haas. In the film, Ford plays a police officer investigating a murder, with his sole witness being a young Amish boy (Haas) who claims that the murderer was a policeman. It was also the feature film debut of Viggo Mortensen, who appears in a minor role.

Directed by Australian-born filmmaker Peter Weir (making his first American film), Witness was filmed on location in Philadelphia, Strasburg and the village of Intercourse in Lancaster County, Pennsylvania. The soundtrack was composed and performed by Maurice Jarre. The film was rated R by the MPAA.

Witness won Academy Awards for Best Original Screenplay and Film Editing. Weir and Ford received nominations for Best Director and Best Actor respectively, and the film was nominated for Best Picture.