Claros (Greek: Κλάρος, Klaros; Latin: Clarus) was an ancient Greek sanctuary on the coast of Ionia. It contained a temple and oracle of Apollo, honored here as Apollo Clarius. It was located on the territory of Colophon, one of the twelve Ionic cities, twelve kilometers to the north. The coastal city Notion lay two kilometers to the south. The ruins of the sanctuary are now found north of the modern town Ahmetbeyli in the Menderes district of Izmir Province, Turkey.
According to legend the oracle at Claros advised the citizens of Smyrna to move from Old Smyrna to the new Smyrna on Mount Pagos (modern Kadifekale), which was refounded there by Alexander the Great. The Smyrnaeans decided to follow up on the advice. Old Smyrna had lost its importance at the time, but after its second foundation it would become one of the most prosperous cities of Asia.
Many monuments were erected in the Roman period (Pompey, Lucullus, Quintus Tullius Cicero); several took place above Hellenistic foundations. Pliny the Elder remarks that "At Colophon, in the cave of the Clarian Apollo, there is a pool, by the drinking of which a power is acquired of uttering wonderful oracles; but the lives of those who drink of it are shortened". Iamblichus said that the oracle, during the ecstasy “... is not in control of himself and does not follow what he is saying, or where he is..." Germanicus famously visited the oracle in 18 AD (a year before his death) and "It was said that he prophesied to Germanicus, in dark hints, as oracles usually do, an early doom".