Diotimus of Adramyttium was a Hellenistic epic poet from the city of Adramyttium in Mysia during the 3rd century BCE. No details of his life or education survive.

His only known work is the Amazonis, a lost epic poem known from a two-line fragment preserved by the grammarian Herodian. The fragment describes the Amazons as "spear-brandishing."

Diotimus is a minor figure whose work exemplifies the Hellenistic trend of composing shorter, learned epics on specific mythological themes. His preservation primarily through grammatical citations is typical for many minor poets of the period.