Megalopolis (Greek for large city, great city) may refer to:
- Megalopolis (city type), an extensive metropolitan area or a long chain of continuous metropolitan areas.
- See also, Megacity, Agglomeration, or Ecumenopolis.
- Megalopolis, Greece, now known as Megalópoli.
- Aphrodisias, a small city in Caria, Asia Minor, previously named Megale Polis.
- Doomed Megalopolis, an anime rendition of the Japanese literary epic Teito Monogatari.
- Megalópolis (shortfilm), a shortfilm by Brazilian director Leon Hirszman.
- Megalopolis, the name of a film project by Francis Ford Coppola.