Jorge Juan y Santacilia was born on January 5, 1713, in Novelda, Alicante, Spain. His parents, Bernardo Juan y Cancia and Violante Santacilla y Soler, were hidalgos, the lower aristocracy. Both of his parents were widowed and remarried. They lived in their house on the Plaza del Mar in Alicante and only vacationed in Novelda.
Santacilia orphaned at the age of three, and his two uncles took care of him and his education.