John Ritter (1948–2003) was an American actor.
John Ritter may also refer to:
- John Ritter (congressman) (1779–1851), American legislator from Pennsylvania
- John Ritter (racing driver) (1910–1948), American racing driver
- John H. Ritter (born 1951), American novelist, short story writer, teacher, and lecturer
- John D. Ritter, vocalist for American metalcore band Myka Relocate