Nesvizh Castle is a residential castle of the Radziwill family in Niasviž in Belarus.
In 1582 Mikołaj Krzysztof "Sierotka" Radziwiłł, the Marshal of Lithuania, voivode of Trakai and Vilnius and castellan of Šiauliai, started the construction of an imposing square three-storey chateau. Although the works were based on a pre-existing structure of a mediæval castle, the former fortifications were entirely turned into a renaissance-baroque house. Construction was completed by 1604, and they added several galleries half a century later. The château's corners were fortified with four octagonal towers.
n 1939, the Radziwill family was expelled from the castle by the invading Red Army. In Soviet times, the chateau was used a sanatorium, while the park gradually fell in neglect.
In 1994, the castle complex was designated the national historical and cultural reserve. Twelve years later, the castle complex was inscribed on the World Heritage List.