Telephus the Grammarian was a Greek scholar active during the 2nd century CE in the Roman Empire. As a grammarian, he was a specialist in the Greek language and its literature, presumably working within the educational framework of the eastern Roman provinces. Details of his personal life are virtually unknown, and an association with the city of Pergamon remains uncertain and disputed.

He is known solely for a work titled On Diction in Homer, a specialized treatise analyzing the vocabulary and language of Homeric epic. The book itself is lost and survives only in fragments preserved within the works of later scholars. These fragments are found chiefly in the marginal scholia of medieval Homeric manuscripts and in ancient lexicons.

Modern scholarship views Telephus as a minor but representative figure in the tradition of ancient literary scholarship. His significance rests on his contribution to Homeric studies, illustrating the meticulous textual analysis practiced by grammarians. The fragmentary preservation of his work demonstrates a common pattern, where the notes of individual experts were absorbed into the broader, cumulative body of commentary transmitted over centuries. Later lexicographers, including Hesychius of Alexandria, found his explanations of rare Homeric words useful enough to quote, thereby securing his modest place in the history of classical scholarship.