The Aleuadae (Ancient Greek: Ἀλευάδαι) were an ancient Thessalian family of Larissa who claimed descent from the mythical Aleuas. The Aleuadae were the noblest and most powerful among all the families of Thessaly, whence Herodotus calls its members "rulers" or "kings" (βασιλεῖς).
The first Aleuas, who bore the epithet of Pyrrhos (Πύρρος), that is, "red-haired", is called king, or Tagus, of Thessaly, and a descendant of Heracles through Thessalus. Aleuas played no role his eponymous dynasty outside his kinship's veneration of him at an unidentified sanctuary in Thessaly, but Aelian recorded the myth of how he became a divinely-inspired seer, in the fashion of a gift from a serpent: while he was tending sheep on the slopes of Mount Ossa, a serpent became enamored of him, kissed his hair, licked his face and brought him gifts. According to the Bibliotheca, a grateful brood of serpents, in return for his having erected a funeral pyre for their serpent-mother, purified his ears with their tongues, so that he might understand the language of birds, and interpret their flight in augury.
Plutarch wrote that he was hated by his father on account of his haughty and savage character; but his uncle nevertheless contrived to get him elected king and sanctified by the god of Delphi. His reign was more glorious than that of any of his ancestors, and the nation rose in power and importance. This Aleuas belongs to the mythical period of Greek history. According to Aristotle the division of Thessaly into four parts took place in the reign of the first Aleuas. German philologist Philipp Karl Buttmann places this hero in the period between the so-called return of the Heraclids and the age of Peisistratus.