Ket may refer to:
- Places and peoples
- Ket people, a people of Siberia
- Ket language, the language of the Ket people
- Ket River, a river in Siberia
- Keť, a village in south-west Slovakia
- Fictional literature
- Ket (Greyhawk), a fictional nation in the Dungeons and Dragons World of Greyhawk campaign setting
- Ket, a Djelibeybian god in Discworld
- Mythology
- Ket, thought to be a name of the Celtic legendary figure Ceridwen
- Cet mac Mágach, character in Irish myth
- Other
- Ketamine, a general dissociative anaesthetic
- The right part, of bra-ket notation
- Ket, a girl's name.