"I'm a Cuckoo" is the second single from Scottish indie pop band Belle & Sebastian's sixth studio album, Dear Catastrophe Waitress (2003). Produced by Trevor Horn, the track was released as a single on 16 February 2004. B-side "Stop, Look and Listen" merges into "Passion Fruit" at the end of a song—an instrumental piece which was performed live prior to its release. The front cover features Shantha Roberts.

"I'm a Cuckoo" fared better on the UK Singles Chart than previous single "Step into My Office, Baby", reaching number 14. It is the only Belle & Sebastian song to chart in Spain, peaking at number 19, and was their most recent hit in Sweden, reaching number 59. A Japanese version of the song was released as a B-side to the Japanese version of Belle & Sebastian's subsequent EP, Books.