In C

In C is a composition by Terry Riley from 1964. It is one of the most successful works by an American composer and a seminal example of minimalism. The score directs any number of musicians to repeat a series of 53 melodic fragments in a guided improvisation.

Terry Riley's 1968 recording of In C, released on Columbia Records, was added to the National Recording Registry of the United States Library of Congress in 2022. The piece has inspired many minimalist and postminimalist composers, including Philip Glass and Steve Reich as well as pop and rock musicians.