Greek (Rhodian) Stoic philosopher. Born c. 185 BCE, died 109 BCE.

The first exponent of what is sometimes called "middle Stoicism", Panaitios weighted ethics over logic and natural philosophy. It is likely, from what we know of him, that he preferred practical, "common people"-oriented ethical philosophy, over the more abstract ideal of wisdom that the Stoics originally favoured. In particular, he renounced the radical Cynical aspects of the "old Stoicism".

Panaitios had close relations with many leading Romans of his time, and Cicero made extensive use of Panaitios' (now regrettably lost) work on duty, when he wrote his own De Officiis ("On Duty", 44 BCE).