A pioneering British progressive jazz-rock band, mixing progressive rock and jazz-based improvisation.

The band was formed in 1968 by drummer Jon Hiseman, tenor sax player Dick Heckstall-Smith and bass player Tony Reeves, who had previously worked together in John Mayall's Bluesbreakers. Dave Greenslade, on organ, was immediately recruited.

HIseman disbanded Collosseum in 1971, but the band reunited in 1994 with a stronger orientation towards jazz-fusion rock. His wife, saxophonist Barbara Thompson, joined the band on various occasions before the death of Dick Heckstall-Smith in 2004 and has been since a permanent member of the band.