Demetrius the Younger was a Hellenistic comic poet active in the 4th–3rd centuries BCE. He is distinguished by his epithet from an earlier comic poet named Demetrius. The Byzantine encyclopedia Suda provides the primary record of his existence, though no biographical details survive.

According to the Suda, he authored two comedies: The Tarentines and The Sicilian. Both works are lost, and no fragments survive. Their titles suggest settings in southern Italy and Sicily, locales common in the period's comedy.

His significance is minimal, known only as a catalogued name that helps map Hellenistic comic production. The need for the epithet "the Younger" implies a more prominent predecessor of the same name. The complete loss of his work precludes any assessment of his literary style.