Illyrian (Ἰλλυρική) refers to the group of languages spoken by the ancient Illyrians, a collection of tribes who lived in the western Balkans and the eastern coasts of the Adriatic Sea. These languages are part of the Indo-European language family, although little is known about them due to the scarcity of written records.

Most of what is known about the Illyrian languages comes from personal names, place names, and a few inscriptions. The exact classification and relationship of these languages to other Indo-European languages remain subjects of scholarly debate.

The Illyrian culture and their languages gradually declined with the Roman conquest and subsequent Romanization of the region, leading to the eventual disappearance of the Illyrian languages. Nowadays, they are a topic of historical and linguistic interest.