Alexander of Aphrodisias was a Greek philosopher who lived and worked in the late second and early third centuries CE. He originated from the city of Aphrodisias in Asia Minor but moved to Athens, where he held the officially appointed chair in Aristotelian philosophy. He dedicated this position to the emperors Septimius Severus and Caracalla.

A leading figure in the Peripatetic school, Alexander served primarily as a commentator and defender of Aristotle's works, earning him the ancient nickname "the Commentator." His surviving writings include detailed commentaries on several of Aristotle's texts, such as the Prior Analytics, Topics, and Metaphysics. He also authored independent philosophical treatises, the most famous being On Fate, which argues against Stoic determinism, and On the Soul.

Modern scholars regard Alexander as the most important interpreter of Aristotle from antiquity. His clear explanations aimed to systematize Aristotle's thought and to argue against rival schools like Stoicism and Platonism. His theory of the intellect, which distinguished between the human mind and a divine active intellect, was especially influential. This idea profoundly shaped later medieval philosophy in both the Islamic world and Latin Europe. For centuries, his commentaries were essential guides for the study of Aristotle.