Orontes I (Old Persian: *Arvanta-; died 344 BC) was a military officer of the Achaemenid Empire and satrap of Armenia at the end of the 5th-century BC and first half of the 4th-century BC. He is notable for having led the unsuccessful Great Satraps' Revolt in Asia Minor against the Achaemenids from 362/1 BC to 360/359 BC. He was the son of Artasyrus, a high-ranking Bactrian nobleman.
Through his maternal line, Orontes traced his descent back to the Persian magnate Hydarnes, one of the six companions of the King of Kings Darius the Great (). Orontes first appears in records in 401 BC as the satrap of Armenia. There he participated in the Battle of Cunaxa, where he pursued the Ten Thousand following their retreat. In the same year, he married Rhodogune, a daughter of Artaxerxes II ().
In the 380s BC, Orontes along with the satrap Tiribazus were assigned to lead the campaign against Evagoras I (), the king of Salamis in Cyprus. The campaign was initially successful, with Evagoras offering to make peace. However, after the negotiations between him and Tiribazus failed, Orontes accused the latter of deliberately prolonging the war and planning to declare independence.
This led to Tiribazus' dismissal and imprisonment, triggering a chain of events which ultimately weakened the Persian forces, forcing Orontes to make peace with Evagoras in 380 BC. Artaxerxes II did not deem the conclusion of the war satisfactory, and as a result Orontes fell into disfavour.