Arybbas (Ancient Greek: Ἀρύββας[1] or Ἀρύβας;[2] ruled 370–343/2 BC) was a king of the Molossians.
It is very probable that the Aryptaeus, king of the Molossians mentioned by Diodorus 18.11.1, who joined the Hellenic cause during the Lamian War, is Arybbas.
Arybbas' second son was Aeacides king of Epirus (ruled 331-316, 313 BC).
Upon the death of their father Alcetas I in 370 BCE, Arybbas and his brother Neoptolemus I divided the kingdom of Epirus in two and each ruled their own part, until Neoptolemus died around 360 BCE and Arybbas became king of all of Epirus.
[3] Arybbas ruled Epirus until 343/2 BC, when he was driven into exile by Philip II, who placed Alexander I on the throne.