Quadrophenia is a double album released by The Who on October 19 1973, the second of the group's two full-scale rock operas. Its story involves social, musical, and psychological happenings from an English teenage perspective, set in London and Brighton in 1964 and 1965.

The name is a variation on the incorrect popular usage of the medical diagnostic term schizophrenia as multiple personality disorder to reflect the four distinct personalities of Jimmy, the opera's protagonist--each said to represent the personality of one member of The Who. It was also tied in to the Quadraphonic sound schemes then being introduced.