Prince Gaetan of the Two Sicilies, Count of Girgenti (Italian: Gaetano Maria Federico, Principe di Borbone delle Due Sicilie, Conte di Girgenti) (12 January 1846, Naples, Two Sicilies – 26 November 1871, Lucerne, Switzerland) was the seventh child of Ferdinand II of the Two Sicilies and his wife Maria Theresa of Austria. Gaetan was a member of the House of Bourbon-Two Sicilies and consort to Isabella, Princess of Asturias, twice the recognized heir presumptive to the throne of Spain. Through this union, Gaetan was created an Infante of Spain.

Gaetan married Isabella, Princess of Asturias, eldest surviving child of Francis, Duke of Cádiz and his wife Isabella II of Spain, on 13 May 1868 in Madrid. Gaetan was a first cousin to both of Isabella's parents. Their union was intended to end a feud between the Neapolitan Bourbons and the Spanish Bourbons following Spain's recognition of the Kingdom of Italy unified under the House of Savoy. The ceremony took place shortly before Spain's Glorious Revolution which brought an end to Isabella II's reign.