William John Evans (August 16, 1929 – September 15, 1980) was an American jazz pianist and composer who worked primarily as the leader of his trio. His extensive use of impressionist harmony, block chords, innovative chord voicings, and trademark rhythmically independent "singing" melodic lines continue to influence jazz pianists today.

Born in Plainfield, New Jersey, Evans studied classical music at Southeastern Louisiana College and the Mannes School of Music, in New York City, where he majored in composition and received an artist diploma. In 1955, he moved to New York City, where he worked with bandleader and theorist George Russell. In 1958, Evans joined Miles Davis's sextet, which in 1959, then immersed in modal jazz, recorded Kind of Blue, the best-selling jazz album of all time.