The Illyrians are a group of Indo-European tribes in antiquity who inhabit part of the western Balkans and the southeastern coasts of the Italian peninsula (Messapia).

The territory the Illyrians inhabitcomes to be known as Illyria to Greek and Roman authors, who identify a territory that corresponds to parts of Albania and the former Yugoslavia, between the Adriatic Sea in the west, the Drava river in the north, the Morava river in the east and the mouth of the Vjosë river in the south.

The first account of Illyrian peoples comes from the Periplus of Pseudo-Scylax, an ancient Greek text of the middle of the fourth century BCE that describes coastal passages in the Mediterranean.

The name "Illyrians", as applied by the ancient Greeks to their northern neighbors, may have referred to a broad, ill-defined group of peoples, and it is today unclear to what extent they were linguistically and culturally homogeneous.

In fact, an Illyric origin was and still is attributed also to a few ancient peoples in Italy, in particular the Iapyges, Dauni and Messapi, as it is thought that, most likely, they had followed Adriatic shorelines to the peninsula, coming from the geographic "Illyria".

The Illyrian tribes never collectively regarded themselves as 'Illyrians', and it is unlikely that they used any collective nomenclature for themselves.

However, the name Illyrians seems to be the name applied to a specific Illyrian tribe, which was the first to come in contact with the ancient Greeks during the Bronze Age, causing the name Illyrians to be applied to all people of similar language and customs.

The term "Illyrians" last appears in the historical record in the 7th century, referring to a Byzantine garrison operating within the former Roman province of Illyricum.

All the remaining tribes except perhaps the Romanized Vlachs are Slavicised in the course of the early Middle Ages.

The modern Albanian language might have descended from a southern Illyrian dialect.