Arvanites (Greek: Αρβανίτες, Arvanitika: Arbëreshë or Αρbε̰ρεσ̈ε̰) are a population group in Greece who traditionally speak Arvanitika, a dialect of the Albanian language. They settled in Greece during the late Middle Ages and were the dominant population element of some regions of the Peloponnese and Attica until the 19th century. Arvanites today self-identify as Greeks as the result of a process of assimilation, and do not consider themselves to belong to Albania or the Albanian nation. They call themselves Arvanites (in Greek) and Arbëror (in their language); the communities in northern Greece also use the term Shqiptar (the same used by Albanians of Albania), a term strongly disliked by all the other Arvanites, who also resent being called Albanians. Arvanitika is in a state of attrition due to language shift towards Greek and large-scale internal migration to the cities and subsequent intermingling of the population during the 20th century.

Arvanites in Greece originated from Albanian settlers who moved south at different times between the 13th and 16th century from areas in what is today southern Albania.^{[page needed]} The reasons for this migration are not entirely clear and may be manifold. In many instances the Arvanites were invited by the Byzantine and Latin rulers of the time. They were employed to re-settle areas that had been largely depopulated through wars, epidemics, and other reasons, and they were employed as soldiers. Some later movements are also believed to have been motivated to evade Islamization after the Ottoman conquest. The main waves of migration into southern Greece started around 1300, reached a peak some time during the 14th century, and ended around 1600. Arvanites first reached Thessaly, then Attica, and finally the Peloponnese.