Dositheus of Pelusium was a Hellenistic historian active in the 3rd century BCE. He originated from the Egyptian city of Pelusium in the Nile Delta. No details of his life or education survive.

His only known work is On the Priesthood of the Jews (or On the Jews), which is now lost. It survives only in fragments cited by later authors, notably Josephus in Against Apion and Clement of Alexandria.

Dositheus is a minor figure in Greek historiography, but his work forms part of the early Hellenistic ethnographic literature about Jews written by non-Jewish authors. Josephus used his testimony to argue for the antiquity of the Jewish people against detractors. The fragments remain a source for studying early Hellenistic perceptions of Judaism.