Concepción (Spanish pronunciation: [konseβˈsjon] ^ⓘ; originally: Concepción de la Madre Santísima de la Luz, "Conception of the Blessed Mother of Light") is a city and commune in south-central Chile, and the geographical and demographic core of the Greater Concepción metropolitan area, it is the second largest city in Chile by urban area and one of the three major conurbations in the country. It has a significant impact on domestic trade being part of the most heavily industrialized region in the country. It is the seat of the Concepción Province and the capital of the Biobío Region. It sits about 500 km south of the nation's capital, Santiago.

The city was first settled in the Bay of Concepción, in the zone that would later become the commune of Penco, now part of the Concepción conurbation. The city's demonym, penquista, comes from the place of its original foundation. The city center and historic district is located in the Valle de la Mocha (La Mocha Valley), where it relocated after serious damage left by an earthquake in 1751.

The origin of Concepción dates back to 1550, when it was founded by Pedro de Valdivia as part of the Spanish Empire, under the name of Concepción de María Purísima del Nuevo Extremo, and was the capital of the Kingdom of Chile between 1565 and 1573, retaining the unofficial position of military capital for the rest of the colonial period. The city was an important site in the struggle for Chile's independence, with the Chilean declaration of Independence being held at Concepción's Plaza de la Independencia. Until the election of Manuel Montt in 1851 as president, executive power in independent Chile was dominated by Concepción elites.

The city is a known college town in Chile, as it is home to numerous educational institutions, including the University of Concepción, the University of the Bío Bío, and the Catholic University of the Most Holy Conception. The commune also contains various historical bridges, murals, parks and lakes, as well as important cultural venues such as the Teatro Biobío, the Casa del Arte, the local Natural History Museum, and the Teatro Universidad de Concepción.

Concepción was founded by Don Pedro de Valdivia in 1550 north of the Bío Bío River, at the site which is today known as Penco. At that time it was given the name Concepción de María Purísima del Nuevo Extremo (Mary Immaculate Conception of the New End). The new settlement of Concepción was just a few kilometers north of La Frontera (The Frontier), the boundary between Spanish territory and the land of the Mapuche, an American Indian ethnic group that remained independent until the 1870s. The settlement was formally recognized by the Spanish authorities as a town two years later by a royal decree. It was given a coat-of-arms that is still in use today.

At the time of the Spanish arrival to the Concepción area chronicler Jerónimo de Vivar noted local Mapuches wore gold and silver bracelets and "sort of crowns". This is interpreted either as Incan gifts, war spoils from defeated Incas, or the adoption of Incan metallurgy.

Although Concepción was a significant military settlement for the Captaincy General of Chile, it was overrun and destroyed by Mapuche armies in 1554, and once again after being refounded in 1555. Concepción was restored during the governorship of García Hurtado de Mendoza when he landed there and built a fort on the Alto de Pinto in 1557. The town was refounded once more on January 6, 1558, by captain Jerónimo de Villegas. It became the headquarters of the military forces engaged against the Mapuche in La Araucanía over the next two centuries, growing to a population of 10,000 despite a siege in 1564 and other attacks by the Mapuche. Concepción was the home of the Real Audiencia from 1565 to 1575.

Earthquakes and tsunamis, which razed the town in 1570, 1657, 1687, 1730 and 1751, led the authorities to move the town to its current site in the Valle de la Mocha, alongside the Bío Bío River; the old site lay empty until March 29, 1842, when the present town of Penco was founded.