Rapperswil Castle (Swiss German: Schloss Rapperswil) is a castle, built in the early 13th century by the House of Rapperswil, in the formerly independent city of Rapperswil. The castle is located on the eastern Zürichsee's western Obersee lakeshore in Rapperswil, a locality of the Rapperswil-Jona municipality in Switzerland's canton of St. Gallen.