Illyrian religion refers to the religious beliefs and practices of the Illyrian peoples, a group of tribes who spoke the Illyrian languages and inhabited part of the western Balkan Peninsula from at least the 8th century BC until the 7th century AD. The available written sources are very tenuous. They consist largely of personal and place names, and a few glosses from Classical sources.
Still insufficiently studied, the most numerous traces of religious practices of the pre-Roman era are those relating to religious symbolism. Symbols are depicted in every variety of ornament and reveal that the chief object of the prehistoric cult of the Illyrians was the Sun, worshipped in a widespread and complex religious system. The Illyrian Sun-deity is figuratively represented on Iron Age plaques as the god of the sky and lightning, also associated with the fire altar where he throws lightning bolts. Illyrian deities were mentioned in inscriptions on statues, monuments, and coins of the Roman period, and some interpreted by Ancient writers through comparative religion. To these can be added a larger body of inscriptions from the south-eastern Italian region of Apulia written in the Messapic language, which is generally considered to be related to Illyrian, although this has been debated as mostly speculative. There appears to be no single most prominent god for all the Illyrian tribes, and a number of deities evidently appear only in specific regions.