The name Pelasgians is used by some ancient Greek writers to refer to populations that were either the ancestors of the Greeks or who preceded the Greeks in Greece.

In general, "Pelasgian" has come to mean more broadly all the indigenous inhabitants of the Aegean Sea region and their cultures before the advent of the Greek language.

This is not an exclusive meaning, but other senses require identification when meant.

During the classical period, enclaves under this name survive in several locations of mainland Greece, Crete and other regions of the Aegean.

Populations identified as "Pelasgian" speak a language or languages that at the time Greeks identify as "barbaric", even though some ancient writers describe the Pelasgians as Greeks.

A tradition also survives that large parts of Greece had once been Pelasgian before being Hellenized.

These parts generally all within the ethnic domain that by the 5th century BCE is attributed to those speakers of ancient Greek who are identified as Ionians.The classification of the Pelasgian language(s), known only from non-Greek elements in Ancient Greek and detectable in some placenames, even whether or not Pelasgian was a single language, and the relationship of Pelasgians to prehistoric Hellenes are long-standing questions that have not received definitive answers.

The field of study looks forward to additional evidence that may fill in the gaps.

Many past and current theories exist.

Some of them are colored by contemporary nationalist issues, which compromise their objectivity.

Archaeological excavations during the 20th century have unearthed artifacts in areas traditionally inhabited by the Pelasgians such as Thessaly, Attica, and Lemnos.

Archaeologists excavating at Sesklo and Dimini have described Pelasgian material culture as Neolithic; others have related to Pelasgians material culture that is "Middle Helladic" and even the "Late Helladic" culture of Mycenaean Greece, where the corpus of brief inscriptions are already in an early form of Greek.

Even the linking of archaeological material evidence to linguistic culture is called into question by Walter Pohl and other modern students of ethnogenesis.