She Wore a Yellow Ribbon is a 1949 American Technicolor Western film directed by John Ford and starring John Wayne. It is the second film in Ford's "Cavalry Trilogy", along with Fort Apache (1948) and Rio Grande (1950). With a budget of $1.6 million, the film was one of the most expensive Westerns made up to that time. It was a major hit for RKO. The film is named after "She Wore a Yellow Ribbon", a song popular with the US military.

The film was shot on location in Monument Valley utilizing large areas of the Navajo reservation along the Arizona-Utah state border. Ford and cinematographer Winton C. Hoch based much of the film's imagery on the paintings and sculptures of Frederic Remington. Hoch won the Academy Award for Best Cinematography, Color in 1950. It was also nominated as 1950's Best Written American Western (which the Writers Guild of America awarded to Yellow Sky).