The Molossians were a group of ancient Greek tribes which inhabited the region of Epirus in classical antiquity. Together with the Chaonians and the Thesprotians, they formed the main tribal groupings of the northwestern Greek group. On their northern frontier, they neighbored the Chaonians and on their southern frontier neighbored the kingdom of the Thesprotians. They formed their own state around 370 BC and were part of the League of Epirus. The most famous Molossian ruler was Pyrrhus of Epirus, considered one of the greatest generals of antiquity. The Molossians sided against Rome in the Third Macedonian War and were defeated. Following the war, the region witnessed devastation while a considerable number of Molossians and other Epirotes were enslaved and transported to the Roman Republic, overwhelmingly in the Italian Peninsula itself.

Epirus is a geographical and historical region in southeastern Europe, now shared between Greece and Albania. It lies between the Pindus Mountains and the Ionian Sea, stretching from the Bay of Vlorë and the Acroceraunian Mountains in the north to the Ambracian Gulf and the ruined Roman city of Nicopolis in the south. It is currently divided between the region of Epirus in northwestern Greece and the counties of Gjirokastër and Vlorë in southern Albania. The largest city in Epirus is Ioannina, seat of the Greek region of Epirus, with Gjirokastër the largest city in the Albanian part of Epirus.