In 1946, having been demobbed from the RAF, Ste. Croix matriculated into University College, London (UCL) to study ancient history: he preferred London over Oxbridge, because it offered a history course covering 3000BC to the death of Heraclius in AD641, not classics (with its focus on language and philosophy). His main tutor was A. H. M. Jones, the college's new chair of the Ancient History, who remained an influencing figure on Ste. Croix's work beyond his graduation. He graduated from University College, London with a first-class Bachelor of Arts (BA) degree in 1949. He was awarded a Doctor of Letters (DLitt) degree by the University of Oxford in 1978.