Mentor of Rhodes (Μέντωρ ὁ Ῥόδιος) (c. 385 BC – 340 BC) was a Greek mercenary who fought both for and against Artaxerxes III of Persia. He is also known as the first husband of Barsine, who later became mistress to Alexander the Great. In 358 BC, Mentor, along with his brother Memnon, were hired to provide military leadership by a rebel Persian satrap, Artabazus. Despite Mentor's capable leadership, the rebellion failed, and Artabazus, Barsine and Memnon fled to Macedon, where they were welcomed by Philip II. Mentor fled to Egypt.