Tom Coster (born August 21, 1941) is an American keyboardist and composer. Detroit-born and San Francisco-raised, Coster played piano and accordion as a youth, continuing his studies through college and a productive five-year stint as a musician in the U.S. Air Force Band.

Coster has played with and/or composed for many groups and musicians including The Loading Zone, Gábor Szabó, Carlos Santana, Billy Cobham, Third Eye Blind, Coryell/Coster/Smith, Claudio Baglioni, Stu Hamm, Boz Scaggs, Zucchero and Bobby Holiday, Joe Satriani, Frank Gambale, and Vital Information. Coster also produced several solo jazz fusion recordings as a leader for Fantasy, Headfirst, and JVC.