São Pedro do Sul is a municipality in the state of Rio Grande do Sul, in southern Brazil. It is one of the many municipalities that make up this state, which is Brazil's southernmost and borders Uruguay and Argentina.
The municipality shares its name with São Pedro do Sul in Portugal, a town known for its thermal springs, but the two are separate places in different countries. The Brazilian municipality is located in the interior of Rio Grande do Sul, a state whose economy is largely based on agriculture and livestock.