Amyntas (Ancient Greek: Ἀμύντας), Tetrarch of the Trocmi was a King of Galatia and of several adjacent countries between 36 and 25 BC, mentioned by Strabo as contemporary with himself. He was the son of Brogitarus, king of Galatia, and Adobogiona, daughter of king Deiotarus Philoromaeus.
Amyntas seems to have first possessed Lycaonia, where he maintained more than 300 flocks. To this he added the territory of Derbe by the murder of its prince, Antipater of Derbe, the friend of Cicero, and Isaura and Cappadocia by Roman favour. Originally he had been the king of Cappadocia Deiotarus secretary (γραμματεύς), and was made by Amyntas commander in chief (στρατηγός) of the Galatian auxiliaries sent to help Brutus and Cassius against the Triumvires, but deserted to Mark Anthony just before the battle of Philippi in 42 BC.