Gran Duque D'Alba XO is a long-aged grape brandy from Spanish producer Williams & Humbert that was aged in a solera for over 12 years which use American oak ex-sherry butts. The brandy is then further aged for 6 years in American oak barrels that held Don Guido Pedro Ximénez sherry.

The Gran Duque brand is named after the Great Duke of Alba, Fernando Álvarez de Toledo y Pimentel, a 16th-century Spanish general who advised both King Charles I and King Philip II of Spain.