Bagoas (in Old Persian Bagoi) was an eunuch in the Persian Empire in the 4th Century BCE. He was reportedly the lover of Darius III and after Darius' death, of Alexander the Great. Another eunuch of the same name, a vizier of the empire, deposed one Persian king and was killed by another when this Bagoas, called son of Pharnuches, would have been a young child.