Paquita Sauquillo was born in Madrid on 31 July 1943, the eldest daughter of José Luis Sauquillo and Deseada Pérez del Arco. She had two brothers, José Luis (born 1944), and (born 1947), also a lawyer, who was murdered on 24 January 1977 during the Atocha massacre. Paquita could also have died that night, but she was meeting with the lawyers José María Mohedano and Manuela Carmena at another location.