Bas (Greek: Βᾶς; lived c. 397 BC – 326 BC, ruled 376 BC – 326 BC), first independent ruler of Bithynia, governed fifty years, from 376 to 326 BC, and died at the age of 71.
He succeeded his father Boteiras, and was himself succeeded by his own son Zipoetes I.
He defeated Calas, a general of Alexander the Great, and maintained the independence of Bithynia.