Alfonso Fernández "el Niño" (b. c. 1243 - 1281) was a Spanish noble, the illegitimate son of Alfonso X of Castile, King of Castilla and León, and of Elvira Rodríguez de Villada. He was the Señor de Molina and of Mesa through his marriage to Blanca Alfonso de Molina, daughter of the infante Alfonso of Molina, and niece of King Alfonso IX of León.