The Arauco War was a long-running conflict between colonial Spaniards and the Mapuche people, mostly fought in the Araucanía region of Chile. The conflict began at first as a reaction to the Spanish conquerors attempting to establish cities and force Mapuches into servitude. It subsequently evolved over time into phases comprising drawn-out sieges, slave-hunting expeditions, pillaging raids, punitive expeditions, and renewed Spanish attempts to secure lost territories. Abduction of women and war rape was common on both sides.

The Mapuche are a group of indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging ethnicity composed of various groups who share a common social, religious, and economic structure, as well as a common linguistic heritage as Mapudungun speakers. Their homelands once extended from Choapa Valley to the Chiloé Archipelago and later spread eastward to Puelmapu, a land comprising part of the Argentine pampa and Patagonia. Today the collective group makes up over 80% of the indigenous peoples in Chile and about 9% of the total Chilean population. The Mapuche are concentrated in the Araucanía region. Many have migrated from rural areas to the cities of Santiago and Buenos Aires for economic opportunities, more than 92% of the Mapuches are from Chile.