The Peloponnese (/ˌpɛləpəˈniːz, -iːs/) or Peloponnesus (/ˌpɛləpəniːsəs/; Greek: Πελοπόννησος, romanized: Peloponnesos, IPA: [peloˈponisos]) is a peninsula and geographic region in southern Greece. It is connected to the central part of the country by the Isthmus of Corinth land bridge which separates the Gulf of Corinth from the Saronic Gulf. During the late Middle Ages and the Ottoman era, the peninsula was known as the Morea (Byzantine Greek: Μωρέας), a name still in colloquial use in its demotic form (Greek: Μωριάς).

The peninsula is divided among three administrative regions: most belongs to the Peloponnese region, with smaller parts belonging to the West Greece and Attica regions.