The Palace of the Grand Master of the Knights of Rhodes, also known as the Kastello, is a medieval castle in the city of Rhodes, on the island of Rhodes in Greece. It is one of the few examples of Gothic architecture in Greece. The site was previously a citadel of the Knights Hospitaller that functioned as a palace, headquarters, and fortress.

Rhodes is the principal city and a former municipality on the island of Rhodes in the Dodecanese, Greece. Since the 2011 local government reform, it is part of the municipality Rhodes, of which it is the seat and a municipal unit. It has a population of approximately 56,000 inhabitants. Rhodes has been famous since antiquity as the site of Colossus of Rhodes, one of the Seven Wonders of the Ancient World. The citadel of Rhodes, built by the Hospitalliers, is one of the best-preserved medieval towns in Europe. The Medieval city is designated as a UNESCO World Heritage Site.