Jack Behrens (born 25 March 1935) is a Canadian composer, music educator, and writer of American birth. A member of the Canadian League of Composers and an associate of the Canadian Music Centre, his music has been performed throughout North America and on CBC Radio and radio stations in the United States. In 1970 his orchestral work The Sound of Milo won first prize in the New Orleans Symphony contest and his choral work How Beautiful is the Night was awarded the Francis Boott Prize at Harvard University. He was married to the now-deceased Canadian pianist Sonja Peterson Behrens.
Born in Lancaster, Pennsylvania, Behrens was trained at the Juilliard School where he earned a Bachelor of Music in 1958 and a Master of Music in 1959. Among his teachers at Juilliard were William Bergsma, Vincent Persichetti, and Peter Mennin. In the summer of 1962 he studied at the Aspen Music Festival and School with Darius Milhaud and in the summers of 1964–1965 he studied with Stefan Wolpe and John Cage at the Emma Lake Composers-Artists Workshop in Saskatchewan. He later entered the graduate composition program at Harvard University where he earned a Doctor of Philosophy in music composition in 1973. His teachers at Harvard were Leon Kirchner and Roger Sessions.
In 1962 Behrens joined the music faculty at the University of Saskatchewan where he was head of the theory department through 1966. He worked on the music faculty at Simon Fraser University from 1966–1970 and then taught at California State University from 1970–1976. From 1976–1980 he was chairman of the music theory and composition department at the University of Western Ontario (UWO), and then served as the dean of UWO's music faculty from 1980–1986.