John Maurice Hartman (July 3, 1923 – September 15, 1983) was an American jazz singer celebrated for his smooth baritone voice and heartfelt ballads. He performed and recorded with major jazz figures like Earl Hines, Dizzy Gillespie, and Erroll Garner. Hartman is especially known for his 1963 collaboration with John Coltrane, an album regarded as a high point in jazz vocal recordings.