The Legislature of Río Negro Province (Spanish: Legislatura de la Provincia de Río Negro) is the unicameral legislative body of Río Negro Province, in Argentina. It convenes in the provincial capital, Viedma. It comprises 46 legislators, 22 of whom are elected in a single province-wide multi-member district, while the remaining 24 are elected in eight three-member districts that divide the province's territory, called "electoral circuits" (circuitos electorales). Its powers and responsibilities are established in the provincial constitution.