The Spanish Empire (Spanish: Imperio Español) comprised territories and colonies administered directly by Spain in Europe, in America, Africa, Asia and Oceania. It originated during the Age of Exploration and was therefore one of the first global empires. At the time of Habsburgs, Spain reached the peak of its world power. being the foremost global power. Its establishment in the 15th century ushered in the modern global era and five centuries of European dominance of global affairs. Spain's reach beyond Europe spanned six centuries, from the first voyages to the Americas in 1492 until the independence of its last African colonies in the 1970s.

After the War of the Castilian Succession (1475–1479), Spain had emerged with a personally unified monarchy, with the marriage of the Catholic Monarchs or los Reyes Catolicos between the Queen of Castile and the King of Aragon: the internal and foreign policy was coordinated although the rule was separate. In 1492, the Spanish monarchs completed the Reconquista with the incorporation of Granada to the Kingdom of Castile. That same year Christopher Columbus commanded the first Spanish exploratory voyage west across the Atlantic Ocean, leading to the Discovery of America and Europe's eventual colonial engagement in the New World. The Americas thereby became the focus of Spanish exploration and colonization.