William A. "Bill" Le Sage (20 January 1927, London – 31 October 2001, London) was a British pianist, vibraphonist, arranger, composer and bandleader. His credits include the scores for the films The Tell-Tale Heart (1960), Strip Tease Murder (1961), The Court Martial of Major Keller (1961), Tarnished Heroes (1961), The Silent Invasion (1962) and What Every Woman Wants (1962).
A self-taught musician, after working with several small combos, he joined "Geraldo's Navy" and played on Cunard's transatlantic liner, the Queen Mary sailing to New York, where he worked with Lennie Tristano.
In 1950, Le Sage became the pianist in the Johnny Dankworth Seven, also becoming a member of Dankworth's big band in 1953. He left in 1954 to join the various small groups led by the drummer Tony Kinsey, another founder-member of the Dankworth Seven and with whom he would stay until 1961. He then joined baritone sax player Ronnie Ross, with whom he would co-lead various line-ups until 1966. During this period, Le Sage also played with Kenny Baker's Dozen. He began writing music for television and films.
During the Sixties Le Sage also played with Jack Parnell's orchestra, the Chris Barber Band and his own group, Directions in Jazz, which included four cellos. He also accompanied visiting American musicians such as Benny Goodman, Dizzy Gillespie and Ben Webster, amongst others.