Maeandrius of Miletus was a Greek historian from Miletus, active in the early Hellenistic period during the late fourth and early third centuries BCE. He is cited by later authors writing on Miletus and the sanctuary of Apollo at Didyma. The epithet "of Miletus" distinguishes him from other individuals of the same name.

He is known for a single, lost work, a local history of Miletus generally referred to as the Milesiaka or History of Miletus. It survives only in fragments, which provide information on the city’s early history, myths, and the oracle at Didyma.

Maeandrius served as an important source for later writers like Athenaeus and Strabo. Strabo relied on him for Miletus’s foundation myths and the history of Didyma. His fragments are crucial for understanding Hellenistic local historiography and the preservation of Ionian regional traditions.