Prince Gaston of Orleans, Count of Eu (French: Louis Philippe Marie Ferdinand Gaston; 28 April 1842 – 28 August 1922) was a French prince and military commander who fought in the Spanish-Moroccan War and the Paraguayan War. He was the first son of Louis, Duke of Nemours and Princess Victoria of Saxe-Coburg and Gotha, and was married to Princess Isabel, daughter of Pedro II of Brazil and heiress to the Brazilian throne.