Álvar Núñez Cabeza de Vaca (c. 1490–c. 1560) was a Spanish explorer who in 1527 joined an expedition to the New World, and because of his reports that he believed the area north of Mexico might be rich in precious metals, other Spanish explorers were later inspired to explore the region.

After landing in Florida in 1527, Cabeza de Vaca and a few others, including the black explorer Estevanico, became separated from the ships. The men built a barge and sailed across the Gulf of Mexico from northern Florida to the islands off the Texas coast, where their ship was wrecked. In 1528 Cabeza de Vaca was imprisoned by the Indians there. He escaped by 1530 and set out on foot through northern Mexico, exploring the region for some five years. Proceeding south, in 1536 Cabeza de Vaca reached Mexico City, which was then the capital of Spain’s North American holdings. He returned to Spain the following year.

In 1541 the explorer led an expedition to the Río de la Plata region (of southern South America) and reached Asunción (in present-day Paraguay) in 1542. Cabeza de Vaca was appointed the Spanish colonial governor of Paraguay, a position he held for two years. He proved to be an inept leader, was deposed by the colonists, and returned to Spain. There he was banished to service in Africa.