Gaius Memmius may refer to:
- Gaius Memmius (Poet), the poet, orator, tribune of the people in 66 BC, and believed to be the dedicatee of Lucretius' On the Nature of Things
- Gaius Memmius (Tribune), the tribune in 111 BC, who was assassinated in 99 BC by Glaucia so Lucius Appuleius Saturninus could become tribune