Jack Lancaster is a British composer, record producer and musician.

In the late 1960s, Lancaster co-founded the British rock group Blodwyn Pig with Jethro Tull guitarist Mick Abrahams. Since then he has performed live on tour, composed for television and film, performed as a session musician and has produced, written and arranged recording sessions with artists including Phil Collins, Hans Zimmer, Stéphane Grappelli, Brian Eno, Vangelis, Rod Argent and Gary Moore. Lancaster currently lives in Hollywood.