Gytheio (Greek: Γύθειο, [ˈʝiθio]), the ancient Gythium or Gytheion (Ancient Greek: Γύθειον), is a town and a former municipality in Laconia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality East Mani, of which it is a municipal unit. It was the seaport of Sparta, some 40 kilometres (25 miles) north. Gytheio used to be an important port until it was destroyed in 4th century AD, possibly by an earthquake.