A Jesuit reduction was a type of settlement for indigenous people in South America created by the Spanish Jesuit Order during the 17th and 18th centuries. The strategy of the Spanish Empire was to gather native populations into centers called "Indian reductions" (reducciones de indios), in order to Christianize, tax, and govern them more efficiently. The Jesuit interpretation of this strategy was implemented primarily in an area that corresponds to modern-day Paraguay amongst the Tupi-Guarani peoples. Later reductions were extended into areas now part of Argentina, Brazil, and Bolivia.
To understand the impetus behind these Jesuit efforts, one must take into account the widespread belief about the chances of salvation for those outside the Church among Catholics at the time although this attitude has changed. From this came the heroic efforts of missionaries.
Jesuit reductions were different from the reductions in other regions because the indigenous people (Indians) were expected to convert to Christianity but not necessarily adopt European values and lifestyles. Also, unlike the Patronato Real system of missionaries accompanying conquistadores in search of gold in Central America, here it was to remain free from exploitation that the indigenous peoples were sequestered. Under the leadership of both the Jesuits and native caciques, the reductions achieved a high degree of autonomy within the Spanish colonial empire. With the use of Indian labour, the reductions became economically successful. When their existence was threatened by the incursions of Bandeirante slave traders, Indian militia were created that fought effectively against the colonists. The resistance by the Jesuit reductions to slave raids, as well as their high degree of autonomy and economic success, have been cited as contributing factors to the expulsion of the Jesuits from the Americas in 1767.