Acharnes (, before 1915: Μενίδι Menidi) is a suburban town in Attica, Greece. With 106,943 inhabitants (2011 census), it is the most populous municipality in East Attica. It is part of the Athens metropolitan area.

Acharnae (/əˈkɑr.ni/, ) was the largest deme of ancient Attica; it was located in the northwest part of the Attic plain, south of Mt. Parnes in the general vicinity of the modern suburbs of Acharnes and Ano Liosia, about due north of Athens. The Acharnians chiefly grew cereals, grapes, and olives, although Aristophanes in his comedy The Acharnians caricatures them as charcoal-burners. Pindar characterizes them as notably brave.