The Portuguese Empire (Portuguese: Império Português), also known as the Portuguese Overseas Empire (Ultramar Português) or the Portuguese Colonial Empire (Império Colonial Português), was the first global empire in history. In addition, it was the longest-lived of the modern European colonial empires, spanning almost six centuries, from the capture of Ceuta in 1415 to the handover of Macau in 1999 or the grant of sovereignty to East Timor in 2002. The empire spread throughout a vast number of territories that are now part of 53 different sovereign states.

Portuguese sailors began exploring the coast of Africa in 1419, using recent developments in navigation, cartography and maritime technology such as the caravel, in order that they might find a sea route to the source of the lucrative spice trade. In 1488, Bartolomeu Dias rounded the Cape of Good Hope, and in 1498, Vasco da Gama reached India. In 1500, either by an accidental landfall or by the crown's secret design, Pedro Álvares Cabral discovered Brazil on the South American coast. Over the following decades, Portuguese sailors continued to explore the coasts and islands of East Asia, establishing forts and factories as they went. By 1571, a string of outposts connected Lisbon to Nagasaki along the coasts of Africa, the Middle East, India, and Asia. This commercial network brought great wealth to Portugal.