Sosipater was a Greek comic poet who lived during the Hellenistic period, likely in the 2nd century BCE. According to the ancient Byzantine encyclopedia known as the Suda, he came from the city of Sicyon. He is associated with the tradition of New Comedy, which focused on everyday social life and characters.

Only fragments of his work survive. The Suda records the titles of two of his lost comedies: The Miser and The Peloponnesians. Quotations from his plays are preserved by the later writer Athenaeus, who cites them for their descriptions of food, dining customs, and social interactions. These fragments are typical of New Comedy in their focus on domestic and culinary themes.

Sosipater is considered a minor figure in the history of ancient Greek comedy. He represents the generation of comic poets who worked after the more famous playwright Menander. His surviving fragments, though few, are valued by modern scholars for the insight they provide into the language, style, and popular interests of Hellenistic comedy after its classical peak. His work survives today primarily because it was excerpted by later anthologists and grammarians interested in preserving details of ancient daily life.