Infante Alfonso of Spain (Don Alfonso Cristino Teresa Ángelo Francisco de Asís y Todos los Santos de Borbón y Borbón Dos-Sicilias; 3 October 1941 – 29 March 1956) was the younger brother of King Juan Carlos of Spain.

Alfonso was born in Rome, the youngest son of the Infante Juan of Spain, Count of Barcelona and of his wife, Princess Maria Mercedes of Bourbon-Two Sicilies. His godfather was the Infante Alfonso de Orleans y Borbón; his godmother was his father's sister Infanta Maria Cristina of Spain. Within his own family he was called Alfonsito to distinguish him from other family members with the name Alfonso.

When Alfonso was still just a baby, his family moved to Lausanne in Switzerland where they lived in the Villa Les Rocailles. In February 1946 the family moved to Portugal.

In 1947 Alfonso visited Spain for the first time at the invitation of caudillo Francisco Franco. In 1950 he and his brother Juan Carlos were sent to study in Spain. At first they lived in San Sebastián where a private school had been established in the Miramar Palace. In June 1954 they were received by General Franco at the Pardo Palace. Later Alfonso and Juan Carlos attended the military academy in Zaragoza.

On the evening of Maundy Thursday, 29 March 1956, Alfonso and Juan Carlos were at their parents' home Villa Giralda in Estoril, Portugal, for the Easter vacation, where Alfonso died in a gun accident. The Spanish Embassy in Portugal issued an official communiqué:

Alfonso had won a local junior golf tournament earlier on the day, then went to evening Mass and rushed up to the room to see Juan Carlos who had come home for the Easter holidays from military school. It is alleged that Juan Carlos began playing with a .22 caliber revolver that had apparently been given to Alfonso by General Franco. Rumors appeared in newspapers that the .22 caliber revolver had actually been held by Juan Carlos at the moment the shot was fired.

...
Wikipedia