Ferris Bueller's Day Off is a 1986 American teen comedy film written, co-produced, and directed by John Hughes. The film stars Matthew Broderick, Mia Sara, and Alan Ruck, with supporting roles from Jennifer Grey, Jeffrey Jones, Cindy Pickett, Edie McClurg, Lyman Ward, and Charlie Sheen. It tells the story of a charismatic high school slacker, Ferris, who skips school with his best friend Cameron and his girlfriend Sloane for a day in Chicago, regularly breaking the fourth wall to explain his techniques and inner thoughts.

Hughes wrote the screenplay in less than a week. Filming began in September 1985 and finished in November, featuring many Chicago landmarks including the Sears Tower, Wrigley Field, and the Art Institute of Chicago. The film was Hughes's love letter to Chicago: "I really wanted to capture as much of Chicago as I could. Not just in the architecture and landscape, but the spirit."

Released by Paramount Pictures on June 11, 1986, the film became the tenth-highest-grossing film of 1986 in the United States, grossing $70 million over a $5 million budget. The film received generally positive reviews from critics and audiences alike, who praised Broderick's performance, and the film's humor and tone.

In 2014, the film was selected for preservation in the United States National Film Registry by the Library of Congress, being deemed "culturally, historically, or aesthetically significant". The film was followed by a television series, starring Charlie Schlatter as the title character. A spin-off film titled Sam & Victor's Day Off, focusing on the two valets who took Cameron's father's Ferrari on a joy ride, is in development for Paramount+.