The Long Gray Line is a 1955 American Cinemascope Technicolor biographical comedy-drama film in CinemaScope directed by John Ford based on the life of Marty Maher and his autobiography, Bringing Up the Brass, co-written with Nardi Reeder Campion. Tyrone Power stars as the scrappy Irish immigrant whose 50-year career at West Point took him from a dishwasher to a non-commissioned officer and athletic instructor.

Maureen O'Hara, one of Ford's favorite leading ladies, plays Maher's wife and fellow immigrant, Mary O'Donnell. The film co-stars Ward Bond as Herman Koehler, the Master of the Sword (athletic director) and Army's head football coach (1897–1900), who first befriends Maher. Milburn Stone appears as John J. Pershing, who in 1898 swears Maher into the Army. Harry Carey, Jr., makes a brief appearance as the young cadet Dwight D. Eisenhower. (Eisenhower wrote the foreword to Bringing Up the Brass.) Philip Carey plays (fictional) Army football player and future general Chuck Dotson. In addition, actress Betsy Palmer makes her screen debut as Kitty Carter.

The phrase "The Long Gray Line" is used to describe, as a continuum, all graduates and cadets of the United States Military Academy at West Point, New York. Many of the scenes in the film were shot on location at West Point, including the "million dollar view" of the Hudson River near the parade grounds. The film was the last one in which actor Robert Francis appeared before his death at age 25 in an air crash. His rising stardom had reached third billing behind Power and O'Hara at the time of his death.