'''Donatus Magnus''' was a Berber Christian and leader and [[bishop]] of a schismatic Christian group in North Africa during the first half of the fourth century. His name became identified with the schismatic group, the [[Donatism|Donatist]], and to its [[heresy]].

Little is known of his early life. He appeared in history as [[Bishop ]] Donatus of Casae Nigrae the successor in 313 to Majorinus, the schismatic Bishop of Carthage. He has been also referred to as Donatus the Great (Donatus Magnus).

In 316, Donatus represented the schismatics when their dispute with Caecilian over the [[see ]] of Carthage was presented before [[Constantine I]] in Milan. They did not recognize Caecilian as Bishop of Carthage.