Rapperswil-Jona is a municipality in the Wahlkreis (constituency) of See-Gaster in the Canton of St. Gallen in Switzerland. Besides Rapperswil and Jona, which were separate municipalities until 2006, Rapperswil-Jona also includes Bollingen , Busskirch , Curtiberg, Kempraten-Lenggis, and Wagen.

The official language of Rapperswil is (the Swiss variety of Standard) German, but the main spoken language is the local variant of the Alemannic Swiss German dialect.

On 1 January 2007, the municipalities of Rapperswil and Jona merged to form a new political entity. After the merger Rapperswil-Jona had a population of 25,777 (17,799 from Jona and 7,601 from Rapperswil).