Rissa is a former municipality in the old Sør-Trøndelag county in Norway in the Fosen region. The municipality existed from 1860 until its dissolution on 1 January 2018 when it became part of the municipality of Indre Fosen in Trøndelag county. The administrative centre of the municipality was the village of Årnset. Other villages in the municipality included Askjem, Hasselvika, Husbysjøen, Rørvika, Råkvåg, and Stadsbygd.