Eupolis (c. 446 BC-411 BC) was an Athenian poet of the Old Comedy, that flourished in the time of the Peloponnesian War.

Nothing whatever is known of his personal history. With regard to his death, he is said to have been thrown into the sea by Alcibiades, whom he had attacked in one of his plays, but it is more likely that he died fighting for his country.

He is ranked by Horace, along with Cratinus and Aristophanes, as the greatest writer of his school. With a lively and fertile fancy Eupolis combined a sound practical judgment. He was reputed to equal Aristophanes in the elegance and purity of his diction, and Cratinus in his command of irony and sarcasm.

Although be was at first on good terms with Aristophanes, their relations subsequently became strained, and they accused each other, in most virulent terms, of imitation and plagiarism.

Of the 17 plays attributed to Eupolis, with which he obtained the first prize seven times, only fragments remain. Of these the best known were:

• the Kolakes, in which he pilloried the spendthrift Callias, who wasted his substance on sophists and parasites;
• Maricas, an attack on Hyperbolus , the successor of Cleon, under a fictitious name
• the Baptae, against Alcibiades and his clubs, at which profligate foreign rites were practised.

Other objects of his attack were Socrates and Cimon. The Demoi and Poleis were political, dealing with the desperate condition of the state and with the allied (or tributary) cities.