William "Billy" Munn (May 12, 1911, Glasgow - May 2, 2000, Ayrshire) was a Scottish jazz pianist and arranger.
Munn studied at the Athenaeum School of Music, then moved to London and joined the band of Jack Hylton from 1929 to 1936. He also played on recordings with Spike Hughes (1932) and Benny Carter (1936) during this time. Munn then played with Sydney Lipton (1936-40) and concomitantly played with Louis Armstrong and Coleman Hawkins on their tours of England, as well as with Wingy Manone in the United States. He played with Stephane Grappelli in 1943 and George Chisholm in 1944, then led his own ensemble at the Orchid Room in Mayfair from 1945 to 1948. He co-founded the BBC program Jazz Club in the 1940s with Mark White and Harry Parry.
In 1948-49 Munn directed the Maurice Winnick Orchestra at Ciro's club in London, and subsequently led the house band at the Imperial Hotel in Torquay for three decades, from 1949 to 1979. He recorded several times with this group. After 1979 he played solo, mostly locally in Torquay.
A piece by Billy Munn called "Jazzy Interlude" can be found in the video game Fallout 3.