Teresa Cristina was the daughter of the then-Duke of Calabria, who later became King Don Francesco I (Francis I) of the Two Sicilies. Through her father, she was a member of the House of Bourbon-Two Sicilies, also known as Bourbon-Naples, the Italian branch of the Spanish Bourbons. She was a descendant of France's "Sun King", Louis XIV in the male line through his grandson, Don Felipe V (Philip V) of Spain. Teresa Cristina's mother was the "Infanta" "Doña" Maria Isabel (Maria Isabella), daughter of King Don Carlos IV (Charles IV) of Spain, and a younger sister of "Doña" Carlota Joaquina—who was the wife of King Dom João VI of Portugal and the paternal grandmother of Teresa Cristina's future husband.