Praedestinatus was a treatise composed in Rome during the 5th century, when Pope Sixtus III was the Roman Bishop. The treatise attacks predestinarian beliefs taught by Saint Augustine.^[1][2] The treatise is composed of multiple refutations of "heresy", one of them being the "predestinationists".^[2][3]

The author of treatise is unknown, but some have suggested him to have been Arnobius the Younger. The writer appears to have semi-Pelagian views, though still criticizing full-Pelagianism.^[4]