The House of Olivares is a Spanish noble house originating in the Crown of Castile. It is a cadet branch of the House of Medina Sidonia, originating in the sixteenth century.
Historically, the house possessed the lordships of Olivares, Seville; Heliche; Albaida del Aljarafe; Camas, Seville; Castilleja de Guzmán; Castilleja de la Cuesta; Salteras; and Tomares. The most prominent member of the House of Olivares was Gaspar de Guzmán, Count-Duke of Olivares, the favourite of Philip IV of Spain.
The House of Olivares was constituted in 1539 when Charles I of Spain granted Pedro Pérez de Guzmán, son of Juan Alfonso Pérez de Guzmán, 3rd Duke of Medina Sidonia, the title of Count of Olivares (Spanish conde de Olivares). The title comes from the municipality of Olivares in Seville, which was already owned by Pedro Pérez de Guzmán.
In 1625, Philip IV of Spain granted Gaspar de Guzmán, 3rd Count of Olivares, the Duchy of Sanlúcar, at which point he assumed the title of Count-Duke of Olivares (Spanish: conde-duque de Olivares).