Rapperswil Castle is a castle, built in the early 13th century AD by the House of Rapperswil in the former independent city of Rapperswil.
It is located on the eastern Zürichsee respectively western Obersee lakeshore in Rapperswil, a locality of the municipality Rapperswil-Jona in the canton of St. Gallen in Switzerland. Since 1870, the castle has been home to the Polish National Museum established by Polish émigrés, including the castle's lessee and restorer, Count Wladyslaw Broel-Plater. Schloss Rapperswil and the museum are listed in the Swiss inventory of cultural property of national and regional significance as Class A objects of national importance.