Neoplatonism (also called Neo-Platonism) (Greek: Νεοπλατωνισμός), is the modern term for a school of mystical philosophy that took shape in the 3rd century AD, based on the teachings of Plato and earlier Platonists, with its earliest contributor believed to be Plotinus, and his teacher Ammonius Saccas. Neoplatonism focused on the spiritual and cosmological aspects of Platonic thought, synthesizing Platonism with Egyptian and Jewish theology. However, Neoplatonists would have considered themselves simply Platonists, and the modern distinction is due to the perception that their philosophy contained sufficiently unique interpretations of Plato to make it substantially different from what Plato wrote and believed.

The Neoplatonism of Plotinus and Porphyry has been referred to as in fact being orthodox Platonic philosophy by scholars like John D. Turner. This distinction provides a contrast with later movements of Neoplatonism, such as those of Iamblichus and Proclus, which embraced magical practices or theurgy as part of the soul's development in the process of the soul's return to the Source. Possibly Plotinus was motivated to clarify some of the traditions in the teachings of Plato that had been misrepresented before Iamblichus (see Neoplatonism and Gnosticism).