X2: X-Men United

The film's score was composed by John Ottman, a regular collaborator with film director Bryan Singer. The soundtrack album X2: Original Motion Picture Score was released on April 29, 2003. Ottman used a sample of Wolfgang Amadeus Mozart's Requiem as the basis for the music in scenes featuring Nightcrawler. As well as the music on the album, tracks by Conjure One and 'N Sync also featured in the film.

On July 19, 2012, La-La Land Records issued an expanded version of Ottman's score, including the specially recorded version of Alfred Newman's Twentieth Century Fox fanfare incorporating Ottman's film theme.