Duke of Medinaceli (pronounced [meðinaˈθeli]) is an hereditary title in the peerage of Spain, accompanied by the dignity of Grandee.

He also held the title of 5th Count of Medinaceli, which was first awarded in 1368 to his ancestor, Bernal de Foix.

Their grandson Luis, 3rd Count of Medinaceli, eventually inherited the title and changed his family name to "de la Cerda".

He took part in the battles for the "incorporation" of the Kingdom of Navarre on behalf of Ferdinand II of Aragon, the grandfather of King Charles I of Spain.

Juan Francisco de la Cerda y Portocarrero, 8th Duke of Medinaceli, (4 November 1637– 20 February 1691) was a Knight of the Order of the Golden Fleece.

Medinaceli's strategies "produced fierce antipathy" between Marie-Louise of Orleans, the new Queen of Spain.

In 1681, Medinaceli managed to have the Marquis of Villars, the French ambassador, removed from the Spanish court.

[2] In 1685 he fell from power and was replaced by Manual Joaquín Álvarez de Toledo, 8th Count of Oropesa.