San Francisco de Quito, most often called Quito (Spanish pronunciation: [ˈkito]), is the capital city of Ecuador in northwestern South America. It is located in north-central Ecuador in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes mountains. With a population of 1,397,698 according to the last census (2001), and, as estimated by the municipality, approximately 1,504,991 in 2005, Quito is the second most populous city in Ecuador, after Guayaquil. It is also the capital of the Pichincha province and the seat of Metropolitan District of Quito. The canton recorded a population of 1,842,201 residents in the 2001 national census. In 2008 the city was designated as the headquarters of the Union of South American Nations.

The elevation of the city's central square (Plaza de La Independencia or Plaza Grande) is 2,800 m (about 9,186 ft), making Quito the second-highest administrative capital city in the world (after La Paz, Bolivia), and the highest legal capital (ahead of Sucre, also in Bolivia, and Bogotá, Colombia).

The central square of Quito is located about 25 km (15 miles) south of the equator; the city itself extends to within about 1 km (0.6 miles) of zero latitude. A monument and museum marking the general location of the equator is known locally as la mitad del mundo (the middle of the world), to avoid confusion, as the word ecuador is Spanish for equator.

Quito, along with Krakow, were the first World Cultural Heritage Sites declared by UNESCO in 1978.