Terrence Mitchell Riley (born June 24, 1935) is an American composer and performing musician best known as a pioneer of the minimalist school of composition. Influenced by jazz and Indian classical music, his music became notable for its innovative use of repetition, tape music techniques, and delay systems. He produced his best known works in the 1960s: the 1964 composition In C and the 1969 LP A Rainbow in Curved Air, both considered landmarks of minimalism and important influences on experimental, rock, and contemporary electronic music.
Raised in California, Riley began studying composition and performing solo piano in the 1950s. He befriended and collaborated with composer La Monte Young, and later became involved with the San Francisco Tape Music Center. A two-record deal with CBS in the late 1960s, resulting in an LP recording of In C (1968) and A Rainbow in Curved Air (1969), brought his work to wider audiences. In the 1970s, he began intensive studies with Hindustani singer Pandit Pran Nath. He has collaborated frequently throughout his career, most extensively with chamber ensemble the Kronos Quartet and his son, guitarist Gyan Riley.