The Night Lords are one of the legions of Chaos Space Marines in the Warhammer 40,000 universe. They originated on Nostramo, a world which was trapped in a perpetual night and ruled by the primarch Kondrad Curze, who became Night Haunter in the Horus Heresy. They ruled through terror and so were one of the most obvious of the traitor legions. During the heresy Night Haunter was assassinated, supposedly by a Callidus assassin. This misfortune, however, did not slow the Night Lords down and they continued to apply themselves to his mantra and to this day are specialists in terror.

Night lords do not tend to use Daemons in their armies, and indeed with the current rules cannot, with the exception of Furies, Daemons of Chaos Undivded who share the Night Lords fondness for brutal murder and psychological warfare.