The Acharnians or Acharnians is the third play — and the earliest of the eleven surviving plays — by the Athenian playwright Aristophanes. It was produced in 425 BC on behalf of the young dramatist by an associate, Callistratus, and it won first place at the Lenaia festival.

Aristophanes was an Ancient Greek comic playwright from Athens and a poet of Old Attic Comedy. He wrote in total forty plays, of which eleven survive virtually complete today. These provide the most valuable examples of a genre of comic drama known as Old Comedy and are used to define it, along with fragments from dozens of lost plays by Aristophanes and his contemporaries.