The Despotate of the Morea (Greek: Δεσποτᾶτον τοῦ Μορέως, romanized: Despotâton toû Moréōs) or Despotate of Mystras (Greek: Δεσποτᾶτον τοῦ Μυστρᾶ, romanized: Despotâton toû Mystrâ) was a province of the Byzantine Empire which existed between the mid-14th and mid-15th centuries.

Its territory varied in size during its existence but eventually grew to include almost all the southern Greek peninsula now known as the Peloponnese, which was known as the Morea during the medieval and early modern periods.

In 1259, the Principality's ruler William II Villehardouin lost the Battle of Pelagonia against the Byzantine Emperor Michael VIII Palaeologus.

For the larger portion of his reign, Manuel maintained peaceful relations with his Latin neighbors and secured a long period of prosperity for the area.

As Latin power in the Peloponnese waned during the 15th century, the Despotate of the Morea expanded to incorporate the entire peninsula in 1430 with territory being acquired by dowry settlements, and the conquest of Patras by Constantine.

The despots Demetrios and Thomas Palaiologos, brothers of the last emperor, failed to send him any aid, as Morea was recovering from a recent Ottoman attack.

The Mani Peninsula at the south end of the Morea resisted under a loose coalition of the local clans, and that area then came under Venice's rule.