M*A*S*H is a 1970 American black comedy war film directed by Robert Altman and written by Ring Lardner Jr., based on Richard Hooker's 1968 novel MASH: A Novel About Three Army Doctors. The film is the only theatrically released feature film in the M*A*S*H franchise.

The film depicts a unit of medical personnel stationed at a Mobile Army Surgical Hospital (MASH) during the Korean War. It stars Donald Sutherland, Tom Skerritt, and Elliott Gould, with Sally Kellerman, Robert Duvall, René Auberjonois, Gary Burghoff, Roger Bowen, Michael Murphy, and in his film debut, professional football player Fred Williamson. Although the Korean War is the film's storyline setting, the subtext is the Vietnam War — a current event at the time the film was made. Doonesbury creator Garry Trudeau, who saw the film in college, said M*A*S*H was "perfect for the times, the cacophony of American culture was brilliantly reproduced onscreen".

After having a panel screen the film, the Army and Air Force Motion Picture Service initially banned M*A*S*H from being shown at army and air force base theaters because it "reflected unfavorably" on the armed services.

M*A*S*H became one of the biggest films of the early 1970s for 20th Century-Fox and is now considered one of the greatest films ever made. It won the Grand Prix du Festival International du Film, later named the Palme d'Or, at the 1970 Cannes Film Festival, received five Academy Award nominations, including Best Picture, and won for Best Adapted Screenplay. In 1996, M*A*S*H was included in the annual selection of 25 motion pictures added to the National Film Registry of the Library of Congress being deemed "culturally, historically, or aesthetically significant" and recommended for preservation. The Academy Film Archive preserved M*A*S*H in 2000.

The film inspired the television series of the same name, which ran from 1972 to 1983. Gary Burghoff, who played Radar O'Reilly, was the only actor playing a major character who appeared in both the film and the television series. Altman despised the TV series, calling it "the antithesis of what we were trying to do" with the film.