Pleistarchus (in Greek Πλεισταρχος; lived 4th century BC) was son of Antipater and brother of Cassander, king of Macedonia. He is first mentioned in the year 313 BC, when he was left by his brother in the command of Chalcis, to make headway against Ptolemy, the general of Antigonus, when Cassander himself was recalled to the defence of Macedonia. Again, in 302 BC, when the general coalition was formed against Antigonus, Pleistarchus was sent forward by his brother, with an army of 12000 foot and 500 horse, to join Lysimachus in Asia.