Crantor of Soli was a Greek philosopher active in the late 4th and early 3rd centuries BCE. Originally from Soli in Cilicia, he moved to Athens to join Plato's Academy, where he studied under Xenocrates and was a colleague of Polemo. He lived during the early Hellenistic period, as new philosophical schools like Stoicism were emerging.

As a member of the early Academy, Crantor is significant for being one of the first philosophers to systematically interpret Plato's works. His most notable contribution was writing the first known commentary on Plato's dialogue Timaeus. This commentary was highly influential and was used by later Platonists for centuries, helping to establish the Timaeus as a foundational text for theories about the cosmos and creation.

Crantor was also famous for a treatise titled On Grief, which is considered a pioneering work in the genre of consolation literature. Written to comfort a father on the loss of his children, it argued for moderation in mourning. This work was widely admired, cited by Cicero in his own writings on grief, and known to later Greek and Christian authors.

Although his own writings survive only in fragments quoted by later authors, Crantor's role was crucial. He helped bridge the philosophy of Plato's immediate successors with the developing thought of the Hellenistic age. Some scholars note that his ethical definition of the highest good as "life in accordance with nature" shows an early interaction with ideas that would later be central to Stoicism.