“Revolution 9” is a recorded composition that appeared on the Beatles' 1968 self-titled LP release (popularly known as The White Album). The sound collage, credited to Lennon–McCartney, was created primarily by John Lennon with assistance from George Harrison and Yoko Ono. Lennon said he was trying to paint a picture of a revolution using sound. The composition was influenced by the avant-garde style of Ono as well as the musique concrète works of composers such as Edgard Varese and Karlheinz Stockhausen.

The recording began as an extended ending to the album version of “Revolution.” Lennon then combined the unused coda with numerous overdubbed vocals, speech, sound effects, and short tape loops of speech and musical performances, some of which were reversed. These were further manipulated with echo, distortion, stereo panning, and fading.

McCartney argued against including the track on The Beatles. At over eight minutes, it is the longest track that the Beatles officially released.