Deimos, a Greek word for dread, may refer to:
- Deimos (mythology), one of the sons of Ares and Aphrodite in Greek mythology
- Deimos (moon), the smaller and outermost of Mars' two natural satellites
- Deimos-1, an artificial Earth satellite
- Deimos (comics), villain for the Warlord comic series
- DEIMOS, an early message passing OS for the Cray-1, replaced by the Cray Time Sharing System
- DEIMOS, Tech 2 Heavy Assault Ship in Eve-online, internet spaceship game
- Deimos (Doctor Who audio), an audio drama
- Deimos, a character from the God of War series.