Infante Alfonso of Spain, Prince of the Two Sicilies, Duke of Calabria was one of two claimants to the title of the head of the House of Bourbon-Two Sicilies from 1960 until his death in 1964. Alfonso was the son of Prince Carlos of Bourbon-Two Sicilies (1870–1949) and his wife, María de las Mercedes, Princess of Asturias (1880–1904). He was born and died in Madrid, Spain.

The House of Bourbon-Two Sicilies is a cadet branch of the House of Bourbon that ruled Southern Italy and Sicily for more than a century in the 18th and 19th centuries. It descends from the Capetian dynasty in legitimate male line through Philip, Duke of Anjou, a younger grandson of Louis XIV of France (1638–1715) who established the Bourbon dynasty in Spain in 1700 as Philip V (1683–1746). In 1759, King Philip's younger grandson was appanaged with the kingdoms of Naples and Sicily, becoming Ferdinand IV and III (1751–1825), respectively, of those realms. His descendants occupied the joint throne, merged as the "Kingdom of the Two Sicilies" in 1816, until 1861, claimed it thereafter from exile, and constitute the extant Bourbon-Two Sicilies family.