Arsinoë II (, 316 BC–unknown date from July 270 BC until 260 BC) was a Ptolemaic Greek Princess of Ancient Egypt and through marriage was Queen of Thrace, Asia Minor and Macedonia as wife of King Lysimachus (Greek: Λυσίμαχος) and later co-ruler of Egypt with her brother-husband Ptolemy II Philadelphus (Greek: Πτολεμαῖος Φιλάδελφος, which means "Ptolemy the sibling-loving").