Dahak is an evil god in the fictional universe of and . He seems to be based on the evil demon Azhi Dahaka from Zoroastrian mythology, and on the Judeo-Christian concept of Satan. Dahak might also best be described as an evil perversion on the idea of the Judeo-Christian God with key similarities twisted into polar opposites.

Dahak is the name of a planet-sized starship in the Mutineers Moon, the Armageddon Inheritance and Heirs of Empire (all collected in the omnibus volume, Empire from the Ashes) books by David Weber.