The castle of Leuktron (Greek, Modern (1453-);: Λεύκτρον) or Beaufort is a late medieval fortification in the southern Peloponnese.
The fortress was built by the Prince of Achaea, William II Villehardouin, on the eastern shore of the Messenian Gulf, in order to keep at bay the Slavic tribes living on Mount Taygetos. It is located close to the ancient settlement of Leuctra and the modern village of Stoupa, on a large rock rising above the shore, forming a platform some 120m (390feet) long, 50m (160feet) wide, and less than 80m (260feet) high that extends from northeast to southwest. The curtain wall is constructed of irregular-sized stones mixed with brick fragments. Remnants of a square keep and a cistern are still visible in the interior.