The Portuguese Empire, also known as the Portuguese Overseas or the Portuguese Colonial Empire, was composed of the overseas colonies, factories, and later overseas territories, governed by the Kingdom of Portugal. It was one of the longest-lived colonial empires in European history, lasting almost six centuries from the conquest of Ceuta in North Africa in 1415, to the transfer of sovereignty over Macau to China in 1999. The empire began in the 15th century, and from the early 16th century it stretched across the globe, with bases in Africa, North America, South America, and various regions of Asia and Oceania.

Portuguese is a Western Romance language of the Indo-European language family originating from the Iberian Peninsula of Europe. It is the official language of Portugal, Brazil, Cape Verde, Angola, Mozambique, Guinea-Bissau and São Tomé and Príncipe, and has co-official language status in East Timor, Equatorial Guinea, and Macau. Portuguese-speaking people or nations are known as "Lusophones". As the result of expansion during colonial times, a cultural presence of Portuguese speakers is also found around the world. Portuguese is part of the Ibero-Romance group that evolved from several dialects of Vulgar Latin in the medieval Kingdom of Galicia and the County of Portugal, and has kept some Celtic phonology.