(Θεόκοσμος), of Megara, a statuary, whose time is accurately defined by two statements in Pausanias. In the temple of Zeus Olympius at Megara, the traveller saw an unfinished chryselephantine statue of the god, which Theocosmus had undertaken to make, with the assistance of Pheidias, but the execution of which was interrupted by the breaking out of the Peloponnesian War, and the consequent incursions of the Athenians into the Megarensian territory. The face alone was of ivory and gold, and the rest of the statue of mud (or plastic clay) and gypsum ; and behind the temple there lay some half-wrought logs of wood, which Theocosmus had intended to cover with ivory and gold, and to use in completing the statue. Above the head of the god were the Hours and the Fates (Paus. 1.40.3. s. 4).

Theocosmus also made the statue of Lysander's pilot, Hermon, which formed a portion of the great votive offering dedicated by the Lacedaemonians at Delphi, out of the spoils of the battle of Aegospotami (Paus. 10.9.4. s. 8). Hence Theocosmus must have flourished from before the beginning till after the end of the Peloponnesian War, that is, in round numbers, about B. C. 435-430. He was the father of CALLICLES I.