The Temple of Poseidon at Tainaron was an Ancient Greek temple and sanctuary of the god Poseidon. It was situated at the tip of the Mani Peninsula, on the Peloponnese in southern Greece. It was dedicated to the god in the form of his cultic epithet "Poseidon Asphaleius", meaning "Poseidon of Safety". The official name of the god of the sanctuary as attested by literature and inscriptions is "Poseidon at Tainaron". Tainaron was a center for the recruitment of mercenaries and the sanctuary may have been considered an asylum for runaway Greek slaves.
The area was called "Tainaron" or "Tainarios" by the ancient Greeks; the proper modern name of the landform is Cape Matapan although variations of its ancient name are used frequently. The site is the southernmost extent of mainland Greece and the second-southernmost point in mainland Europe.