Sebastián de Belalcázar (1479/1480 – 1551) also written as de Benalcázar, was a Spanish conquistador. He was born Sebastián Moyano in the province of CórdobaSpain. He took the name Belalcázar as that was the name of the castle-town near to his birthplace in Córdoba, and is known as the founder of important early colonial cities in the northwestern part of South America; Quito in 1534 and CaliPasto and Popayán in 1537. De Belalcázar led expeditions in present-day Ecuador and Colombia.

He entered Nicaragua in 1524 during the conquest of Nicaragua, and became the first mayor of the city of León. He remained there until 1527, when he left for Honduras as a result of internal disputes among the Spanish governors. In 1534, while commanding the settlement of San Miguel for Francisco Pizarro, Sebastian set off to conquer Quito in Ecuador, without orders from Pizarro. Quito had been the northernmost city of the Inca Empire, but while Belalcázar defeated the Inca general Rumiñahui, the local population secreted the city treasure away. Belalcázar then founded the new city of Quito with Diego de Almagro and Baltasar Maldonado, honoring Pizarro by naming it in full "San Francisco de Quito".

Moving northward into present day Colombia in search of El Dorado in 1535, he entered the Cauca River Valley, founding the southwestern Colombian cities of Santiago de Cali in 1536, and Pasto and Popayán which he ruled with the title of governor of Popayán. He died of natural causes after being sentenced to death in Cartagena, Colombia in 1551.