William Overton Smith was an American clarinetist and composer. He worked extensively in modern classical music, Third Stream and jazz, and was perhaps best known for having played with pianist Dave Brubeck intermittently from the 1940s to the early 2000s. Smith frequently recorded jazz under the name Bill Smith, but his classical compositions are credited under the name William O. Smith.
Smith was born in Sacramento and grew up in Oakland, California, where he began playing clarinet at the age of ten. He put together a jazz group to play for dances at 13, and at the age of 15 he joined the Oakland Symphony