Misti is a dormant volcano located in the Andes mountains of southern Peru, rising above Peru's second-largest city, Arequipa. It is a conical volcano with two summit craters, one nested within the other. The inner crater contains a lava structure (either a volcanic plug or a lava dome) with active vents that emit volcanic gases. The summit of the volcano lies on the margin of the outer crater at 5,822 metres (19,101 ft) above sea level. Snow covers the summit but does not persist; there are no glaciers. The upper slopes of the volcano are barren, while the lower slopes are covered by bush vegetation.

The volcano developed over four different stages. During each stage, lava flows and lava domes built up a mountain, whose summit then collapsed to form a bowl-shaped depression. The volcano is part of a volcano group with Chachani to the northwest and Pichu Pichu to the southeast, which developed on top of the debris of other volcanoes. Numerous intense explosive eruptions took place during the last 50,000 years and covered the surrounding terrain with tephra (rocks fragmented by volcanic eruptions). The last two significant eruptions were 2,000 years ago and in 1440–1470 AD; since then, phases of increased fumarolic activity have sometimes been mistaken for eruptions.

Misti is one of the most dangerous volcanoes in the world, as it lies less than 20 kilometres (12 mi) from Arequipa. The city's population exceeds one million people and its northeastern suburbs have expanded onto the slopes of the volcano. The narrow valleys on western and southern flanks are particularly threatening, as mudflows and flows consisting of hot volcanic debris could be channelled into the urban area and into important infrastructure, like hydropower plants. Even moderate eruptions can deposit volcanic ash and tephra over most of the city. Until 2005, there was little awareness or monitoring of the volcano. Since then, the Peruvian Geological, Mining and Metallurgical Institute (INGEMMET) has set up a volcano observatory in Arequipa, and run public awareness campaigns on the dangers of renewed eruptions and published a hazard map. The Inca viewed the volcano as a threat and during the 1440–1470 eruption offered human sacrifices (capacocha) on the summit of Misti and neighbouring mountains to placate the volcano; the mummies on Misti are the largest Inca human sacrifice known.

The name "Misti" originates from either the Quechuan language or Spanish. It means 'mixed', 'mestizo' or 'white' and may refer to the volcano's snow cover. The indigenous names are Putina, which means 'mountain that growls' in the Puquina language, while the Aymara language terms for Misti are Anukara or Anuqara ('dog'). All three terms refer to the dog-like appearance of the volcano when viewed from the Andean Plateau, known as the Altiplano. The volcano was originally known as Putina and only became known as Misti beginning in the 1780s. Other names for the volcano are Guagua-Putina, El Volcán ('the volcano'), San Francisco and Volcán de Arequipa ('Arequipa volcano'). Some Spanish chroniclers have confused it with other volcanoes like Ubinas and Huaynaputina.

Settlement of the region began more than 1,500 years ago. It is unclear whether the Inca were the first Altiplano political entities to influence the region or whether previous cultures played a role, but by the arrival of the Spanish, the area was densely populated, and there were canals, roads and buildings where Arequipa is today. The city itself was founded on 15 August 1540, and Misti is featured on its seal. The volcano is the house mountain of Arequipa, whose residents view themselves as the offspring of the mountain.

Misti lies north of Arequipa, the second-largest city in Peru, and is the best known volcano of Peru. The Inca empire's Condesuyos province included the volcano; presently Misti is in the Arequipa Department. The mountain is visible from the Pacific Ocean.

The volcano rises about 3.5 kilometres (2.2 mi) above Arequipa. Dirt roads heading from Arequipa to Chivay run along the northern/western foot of Misti, and those to Juliaca along the southern/eastern foot. Inca roads from the Arequipa area passed by the volcano. There are numerous dams on the Rio Chili, including the Aguada Blanca Dam and reservoir north of the volcano, El Frayle (both north of the volcano) and Hidroeléctrica Charcani I, II, III, IV, V and VI along the northwestern foot of Misti; their hydroelectric power plants provide electricity to Arequipa.

Italian geographer Gustavo Cumin [it] in 1925 stated that three small man-made structures in the crater had been known since 1677, but noted that their origin was unknown. Inca ceremonial platforms on the summit associated with human sacrifices were probably destroyed by human activity around 1900.