The Paleo-Balkan languages are a geographical grouping of various Indo-European languages that were spoken in the Balkans and surrounding areas in ancient times. In antiquity, Dacian, Greek, Illyrian, Messapic, Paeonian, Phrygian and Thracian were the Paleo-Balkan languages which were attested in literature. They may have included other unattested languages.

Paleo-Balkan studies are obscured by the scarce attestation of these languages outside of Ancient Greek and, to a lesser extent, Messapic and Phrygian. Although linguists consider each of them to be a member of the Indo-European family of languages, the internal relationships are still debated. A Palaeo-Balkanic or Balkanic Indo-European branch has been proposed in recent research, comprising the Albanoid or Illyric (Albanian–Messapic), Armenian, and Graeco-Phrygian (Hellenic–Phrygian) subbranches. Regardless of the name, there is no direct evidence to support the location for the hypothetical common ancestor of these languages in the Balkan peninsula itself. Τhe common stage between the Late Proto-Indo-European dialects of Pre-Albanian, Pre-Armenian, and Pre-Greek, is considered to have occurred in the Late Yamnaya period, after the westward migrations of Early Yamnaya across the Pontic–Caspian steppe; also remaining in the western steppe for a prolonged period of time, separated from the Indo-European dialects that later gave rise to the Corded Ware and Bell Beaker cultures in Europe.

Due to the processes of Hellenization, Romanization and Slavicization in the Balkans, the only surviving representatives of the ancient languages of the region are Greek and Albanian. The Albanian language evolved from either Illyrian, often supported for obvious geographic and historical reasons as well as for some fragmentary linguistic evidence, or an unmentioned language that was closely related to Illyrian and Messapic.

Illyrian is a group of Indo-European languages whose relationship to other Indo-European languages as well as to the languages of the Paleo-Balkan group, many of which might be offshoots of Illyrian, is poorly understood due to the paucity of data and is still being examined. The centum or satem character of Illyrian is difficult to detect due to the paucity of the available 'Illyrian' linguistic material and to the dual nature of its interpretation. Today, the only sources of information about the Illyrian language consist of a handful of Illyrian words cited in classical sources, and numerous examples of Illyrian anthroponyms, ethnonyms, toponyms and hydronyms.

Messapian was spoken on the Italian peninsula, but is generally regarded an offshoot from the Paleo-Balkan language area. A grouping of Messapian with Illyrian has been proposed for about a century, but remains an unproven hypothesis due to the fragmentary attestation of Illyrian. The theory is based on classical sources, archaeology, as well as onomastic considerations. Messapian material culture bears a number of similarities to Illyrian material culture. Some Messapian anthroponyms have close Illyrian equivalents.

A grouping of Illyrian with Venetic and Liburnian, once spoken in northeastern Italy and Liburnia respectively, is also proposed. The consensus now is that Illyrian was quite distinct from Venetic and Liburnian, but a close linguistic relation has not been ruled out and is still being investigated. Philistine had been linked to many different Indo-European languages: a pre-Greek substrate of the Pelasgians (by Milan Budimir), Mycenaean Greek, and Illyrian but these theories are mostly speculation.

Another hypothesis would group Illyrian with Dacian and Thracian into a Thraco-Illyrian branch, and a competing hypothesis would exclude Illyrian from a Daco-Thracian grouping in favor of Mysian. The classification of Thracian itself is a matter of contention and uncertainty.

The place of Paeonian remains unclear. Not much has been determined in the study of Paeonian, and some linguists do not recognize a Paeonian area separate from Illyrian or Thracian. Phrygian, on the other hand, is considered to have been most likely a close relative of Greek.