Gaius the Platonist (2nd century) was a Greek or Roman philosopher, and a representative of Middle Platonism. Very little is known about him except that he was the teacher of Albinus, who is known to have published a now lost nine-volume summary of Gaius' lectures on Plato. He taught Platonism in the first half of the 2nd century, but almost nothing is known about his philosophical opinions. It has been speculated that the On Plato and His Doctrine written by Apuleius may have been taken from the lectures of Gaius, but this assertion is now seen as dubious. It has also been thought that the anonymous commentary on the Theaetetus of Plato, which is partially extant, may have come from his school. Porphyry mentions that his works were read in the school of Plotinus.