Timothy Jon Gemmill (born May 28, 1949) is an American jazz musician, composer, arranger, producer, bandleader, graphic designer and entrepreneur, who has been involved in musical projects since the late 1960s.

Most notably; Music Projection Trio (1970–1972), Rorschach (1973–1977), Cozzetti & Gemmill Quartet (1978–1982), Cozzetti & Gemmill[1] (1983–present), Rocka Records (1994–2004), Rocka.com (1999–2004) and Cozgem Records (1981–present).

[citation needed]