The Achaeans (/əˈkiːənz/; Greek: Ἀχαιοί, Achaioi) were one of the four major tribes into which the people of Classical Greece divided themselves (along with the Aeolians, Ionians and Dorians). According to the foundation myth formalized by Hesiod, their name comes from Achaeus, the mythical founder of the Achaean tribe, who was supposedly one of the sons of Xuthus, and brother of Ion, the founder of the Ionian tribe. Xuthus was in turn the son of Hellen, the mythical patriarch of the Greek (Hellenic) nation.
Historically, the members of the Achaean tribe inhabited the region of Achaea in the northern Peloponnese. The Achaeans played an active role in the Greek colonization of southern Italy, founding the city of Kroton (Κρότων) in 710 BC. The city was to gain fame later as the place where the Pythagorean School was founded. Unlike the other major tribes (Ionians, Dorians and Aeolians), the Achaeans did not have a separate dialect in the Classical period, instead using a form of Doric.
The name Ἀχαιοί/Ἀχαιϝοί has been derived by Margalit Finkelberg from Hittite Aḫḫiyawā. However, R. S. P. Beekes doubted the validity of this derivation and suggested a Pre-Greek proto-form *Akaywa-.