Duke of Cádiz, named after the city Cádiz in Andalusia, is a substantive title that has been created four times since 1484 for members of the Spanish royal family. It does not include any land tenure and does not produce any income for the holder.

Rodrigo Ponce de León was a Castilian military leader who was granted the title of Duke of Cádiz in 1484. After the death of the first duke in 1492, the Catholic Monarchs negotiated with Francisca Ponce de León y de la Fuente regarding the abolition of the Marquisate and Duchy of Cádiz, reinstating the city and the titles to the crown after her death.

For centuries, the title remained in abeyance, until the nineteenth century. Since then, the title was held by members of the Spanish branch of the House of Bourbon.

The title was re-created by the Head of the Spanish State, Francisco Franco, in favor of Alfonso de Borbón, the first-born son of the infante Jacques, Duke of Anjou and Segovia, who received his title by decree for the birth of his son Francois. However, Royal Decree No. 1.368, of November 6, 1987, of King Juan Carlos I made the lifetime title and the predicate of royal highness non-transferable to “spouses [and] children” (transitory provisions).^[1] It returned to the Crown on the death of Alfonso de Borbón.