Gaucho (gaúcho in Portuguese) is a term commonly used to describe residents of the South American pampas, chacos or Patagonian grasslands, found principally in parts of Argentina, Uruguay, Southern Chile and Rio Grande do Sul state in southern Brazil. In Brazil it is used to call people born in the Rio Grande do Sul state.

The word gaucho could be described as a loose equivalent to the North American "Cowboy". Like the North American word cowboy, Venezuelan or Colombian llanero, or Chilean huaso, or the Mexican vaquero, the term often connotes the 19th century more than the present day; then gauchos made up the majority of the rural population, herding cows and practicing hunting as their main economic activities.

There are several conflicting hypotheses concerning the origin of the term. It may derive from the Quechua huachu (Indian, from the Indies) . The first recorded uses of the term date from around the time of Argentine independence in 1816.