Peter Alexander Goehr (German: ['ɡøːɐ̯]; 10 August 1932 – 26 August 2024) was a German-born English composer of contemporary classical music and academic teacher. A long-time professor of music at the University of Cambridge, Goehr influenced many notable contemporary composers, including Thomas Adès, Julian Anderson, George Benjamin and Robin Holloway.

Born in Berlin, Goehr's childhood was spent in London surrounded by musicians, including his father, the conductor Walter Goehr. Goehr emerged as a central figure in the Manchester School of post-war British composers, including Peter Maxwell Davies and Harrison Birtwistle, in his early twenties. He joined Olivier Messiaen's masterclass in Paris in 1955. Back in England and working for the BBC, he experienced an international breakthrough in 1957 with his cantata The Deluge in 1957, conducted by his father Walter Goehr. He composed Little Symphony in 1963 as a memorial to his father, arriving at a serialism that allowed expressive freedom. He combined avant-garde techniques with elements from music history in works of many genres including the Piano Trio (1966), the first opera Arden Must Die (1966), the music-theatre piece Triptych (1968–70), the orchestral Metamorphosis/Dance (1974), and the String Quartet No. 3 (1975). He founded the Music Theatre Ensemble in 1967.

Goehr first lectured in the United States, at the New England Conservatory of Music in Boston from 1968 and at Yale University, then at the Southampton University from 1970. He was professor of music at the University of Leeds from 1971 and at Cambridge University from 1976 to 1999. Goehr returned to a more traditional way of composing with Psalm IV in 1976. He wrote the opera Arianna in 1995, setting the libretto of Monteverdi's lost opera. He focused on chamber music in later years.