Oporto (ŏpôrˈtō) [key], Port. Pôrto, city (1991 pop. 310,600), capital of Porto dist. and Douro Litoral, NW Portugal, near the mouth of the Douro River. It is Portugal's second largest city, after Lisbon, and an important Atlantic port. Its outer harbor is at Leixões. Oporto's most famous export is port wine, to which the city gives its name. Cork, fruits, olive oil, and building materials are also exported. Cotton, silk, and wool textiles are milled, wood and leather goods are made, and there are other manufactures.
The ancient settlement, probably of pre-Roman origin, was known as Cale and later as Portus Cale. Oporto was captured by the Moors in 716 and retaken in 1092. The centuries of war depopulated the town. Henry of Burgundy secured the title of duke of Portucalense in the 11th cent., and Oporto thus gave its name to the state that became a kingdom. It was for some time the chief city, although not the capital, of little Portugal.
Wine exports increased after the Methuen Treaty (1703) with England. The creation by the marquês de Pombal of a wine monopoly brought the "tipplers' revolt" (1757) in Oporto. After the French conquest of Portugal in the Peninsular War, Oporto was the first city to revolt (1808). It was retaken by the French but liberated (1809) by Wellington. In 1832, in the Miguelist Wars, Dom Pedro I of Brazil long withstood a siege of the city by his brother, Dom Miguel. Oporto was later a center of republican thought, and in 1891 an abortive republican government was set up there.
The city's most conspicuous landmark is the Torre dos Clérigos, a baroque tower; also noteworthy are the Romanesque cathedral, the two-storied Dom Luis bridge across the Douro (1881–87), the Crystal Palace (1865), the Serralves Museum of Contemporary Art (1999), and Rem Koolhaas's celebrated Casa de Música (2005). Oporto is the site of a public university and several private institutions of higher education.