Megalopoli (Greek: Μεγαλόπολη, romanized: Megalópolē) is a town in the southwestern part of the regional unit of Arcadia, southern Greece. It is located in the same site as ancient Megalopolis (Ancient Greek: Μεγαλόπολις, romanized: Megalópolis, lit. 'large/great city'). When it was founded in 371 BC, it was the first large urbanization in rustic Arcadia. Its theatre had a capacity of 20,000 visitors, making it one of the largest ancient Greek theatres.
Today, Megalopoli has several schools, shops, churches, hotels and other services. The population of Megalopoli in 2021 was 5,344 residents.