Amyntas I (Greek: Ἀμύντας Aʹ; c. 540 – 498 BC) was king of the ancient Greek kingdom of Macedon (540 – 512 / 511 BC) and a vassal of Darius I (512 / 511 – 498 BC). He was a son of Alcetas I of Macedon. He married Eurydice and they had a son Alexander.
Amyntas was a vassal of Darius I, king of the Persian Achaemenid Empire, since 512/511 BC. The history of Macedonia may be said to begin with Amyntas' reign. He was the first of its rulers to have diplomatic relations with other states. In particular, he entered into an alliance with Hippias of Athens, and when Hippias was driven out of Athens he offered him the territory of Anthemus on the Thermaic Gulf with the object of taking advantage of the feuds between the Greeks. Hippias refused the offer and also rejected the offer of Iolcos, as Amyntas probably did not control Anthemous at that time, but was merely suggesting a plan of joint occupation to Hippias.