Peloponnesos (Greek: Πελοπόννησος, sometime Latinized as Peloponnesus or Anglicized as The Peloponnese) is a large peninsula in Greece, forming the part of the country south of the Isthmus of Corinth. Its name derives from the Ancient Greek Mythological Hero, 'Pelops', who supposedly conquered the entire region. Of the name, Peloponnesos, 'Pelop' refers to this hero and 'nesos' refers to island, therefore the name means the Island of Pelops.

In medieval times it was called the Morea from its resemblance to a mulberry-leaf in shape.

Peloponnesos is a Periphery of Greece, consisting of 7 prefectures (Greek: νομοι):