Mazaeus or Mazday (Aramaic: 𐡌𐡆𐡃𐡉 MZDY, Greek: Μαζαῖος Mazaios)[1] (died 328 BC) was an Achaemenid Persian noble, satrap (a type of governor) of Cilicia and later satrap of Babylon for the Achaemenid Empire.

His successor in Cilicia was Arsames, who was ultimately expelled by Alexander the Great.

At the Battle of Gaugamela, Mazaeus commanded the right flank with the Syrian, Median, Mesopotamian, Parthian, Sacian, Tapurian, Hyrcanian, Sacesinian, Cappadocian, and Armenian cavalry.

[2] Alexander left a Macedonian, Apollodorus of Amphipolis, as the military commander of the garrison of Babylon, and another as tax-collector.

The daughter of the Persian king Darius III, Stateira II, was originally betrothed to him, but he died before they could be married.