In C is a musical piece by the composer and performing musician Terry Riley. As one of the first minimalist compositions, it was a response to the modern music that dominated the scene in 1968. It is considered a masterpiece in the genre and served as an inspiration for many composers, classical and otherwise.

The pieces consist of repeating cells and different rhythms, loosely based on the musical structures he had heard and loved in north African music. In total, the compositions consist of 53 short musical phrases. The thing that makes In C so enduring, is that once all its conceptual ideas are stripped away, it's a seriously hypnotic piece of music, full of energy.