Glaucias (; ruled c. 335 – c. 302 BC) was an Illyrian king of the
Taulanti state which dominated Illyrian affairs in the second half of the 4th century BC. Glaucias is first mentioned as bringing a considerable force to the assistance of
Cleitus of Dardania, another Illyrian prince, against
Alexander the Great, in the
battle of Pelium 335 BC. They were, however, both defeated, and Cleitus was forced to take refuge within the Taulantian territories, whither Alexander did not pursue him, his attention being called elsewhere by the news of the revolt of
Thebes.