Doña Fabiola de Mora y Aragón was born on 11 June 1928 in Madrid, Spain, at the , the main residence of the Marqués de Casa Riera. She was the daughter of Don Gonzalo de Mora y Fernández y Riera y del Olmo, 4th Marqués de Casa Riera, 2nd Count of Mora (1887–1957), and his wife, Doña Blanca de Aragón y Carrillo de Albornoz y Barroeta-Aldamar y Elío (1892–1981), daughter of the 6th Marchioness of Casa Torres and Viscountess of Baiguer. Her godmother was Queen Victoria Eugenia of Spain.
