Lucifer Calaritanus (unknown - 371) a bishop of Cagliari, Sardinia, was a fierce opponent of Arianism, which followed the Alexandrian presbyter Arius in teaching that Christ is not truly divine but a created being. To further his rigorously orthodox views, Lucifer of Cagliari founded the Luciferians, a sect that survived in scattered remnants into the early 5th century. In its turn, this sect was attacked by Jerome in his polemic Altercatio Luciferiani et orthodoxi ("Altercation of the Luciferian and the orthodox"), which offers almost all that is known of Lucifer or the sect.

His date of birth and the history of his youth are not known, but he must have been born early in the fourth century. His name demonstrates that "Lucifer" (meaning "light-bringer") was not yet merely a synonym of "Satan" in the 4th century. Hasty references by enthusiastic 19th century biblical scholars assumed from the name that the Luciferians were Satanists.