Ermoupolis, historically known as Ermoupolis or Hermoupolis, is a town and former municipality located on the island of Syros in the Cyclades region of Greece. It serves as the seat of the municipality Syros-Ermoupoli and functions as the capital of the South Aegean region.
The municipal unit of Ermoupolis covers an area of 11.18 km2. Following a local government reform in 2011, it became part of the larger municipality Syros-Ermoupoli.