- This article is about the effect; for other uses, see Sleep (disambiguation).

Creatures who are sleeping are considered flat-footed. Creatures damaged while sleeping will wake up. A sleeping NPC with 4 HD or less will be killed instantly if attacked (coup de grâce).
While the creature is asleep it is immune to any prone conditions, though pre-existing prone conditions remain in effect. Petrification will override the effects of sleep, including the ability to perform a coup de grâce, and the prevention of the prone effect.