Guaraní ("wuarani"), a group of culturally related indigenous peoples of South America., are distinguished from the related Tupi by their use of the Guaraní language.

The traditional range of the Guaraní people is in what is now Paraguay between the Uruguay River and lower Paraguay River, the Corrientes and Entre Ríos Provinces of Argentina, southern Brazil, and parts of Uruguay and Bolivia.

Although their demographic dominance of the region has been reduced by European colonization and the commensurate rise of mestizos, there are contemporary Guaraní populations in these areas.