John Mills-Cockell (born 19 May 1943) is a Canadian composer and multi-instrumentalist, perhaps best known for his ground-breaking work with progressive / avant garde Canadian groups Intersystems and Syrinx, and for his numerous works for radio, television, film, ballet, and stage.

Mills-Cockell was one of the earliest adopters of the Moog synthesizer, and is generally regarded as a pioneer in the field of electronic music.