In the Warhammer Fantasy games (Warhammer 40k and Warhammer Fantasy Battle) created by Games Workshop, Chaos refers to the forces of evil and destruction. The followers of Chaos worship the Chaos Gods (or the Warhammer Chaos Powers). Related concepts include the Warp, otherwise known as the Realm of Chaos.

In Warhammer 40k, the Emperor of Mankind, aka The Emperor, is seen by many as the last defence of humanity against Chaos and the Chaos Gods. He was almost killed in a large Chaos rebellion, the Horus Heresy, and has dwelt in the Golden Throne (a life support machine) ever since.