Istros the Callimachean (Ancient Greek: Ἴστρος ὁ Καλλιμάχειος) was a Greek writer, probably from Paphos.
He was a pupil of Callimachus, and active in the Library of Alexandria.
[1] Seventy-seven fragments of his writings remain, mostly from his four-volume Attica, which discussed the cult, religion, and institutions of Attica in its mythical past, based largely on Atthides.
[2] According to the Suda, a 10th-century encyclopedia, he wrote both prose and verse.
[3] Istros' works exist only in fragments (FGrHist 334).