Mynors was educated at Summer Fields School, Oxford, and then at Eton. He was an undergraduate at Balliol College, Oxford (1922-6), winning the university's Hertford and Craven scholarships. At both Eton and Balliol he was a friend of Cyril Connolly. He was a fellow and classical tutor at Balliol from 1927 until 1944 (with an interval of war work at the Treasury), when he moved to Cambridge as Kennedy Professor of Latin. In 1953 he returned to Oxford as Corpus Christi Professor of Latin. He retired in 1970.
He was well known for authoritative editions of Latin texts, but he was also active in other fields. He played a major part in the early years of the series Nelson's (later Oxford) Medieval Texts, himself contributing an edition of Bede's Ecclesiastical History. He was an expert on Latin manuscripts and produced important catalogues. He was also a skilled translator who was a member of the Literary Committee for the New English Bible.
He was knighted in 1963. Elected a Fellow of the British Academy in 1944, he was an Honorary Member of the American Academy of Arts and Sciences, the American Philosophical Society and the Istituto di Studi Romani. He received honorary degrees from four British universities and from the University of Toronto. He served as president of the Classical Association in 1966.
Roger Mynors was killed in a car crash at the age of 86. "He had been working on his catalogue of the manuscripts in Hereford Cathedral Library, and was driving back to Treago, his country home at St Weonards near the Welsh border. As he left the cathedral he was heard to say that he had had a good day".
- R.A.B. Mynors, Cassiodori senatoris Institutiones, Oxford: Clarendon Press, 1937.
- R.A.B. Mynors, Durham cathedral Manuscripts before 1200, Oxford University Press for Durham Cathedral, 1939
- R.A.B. Mynors, C. Valerii Catulli Carmina, Oxford: Clarendon Press, OCT, 1958.
- R.A.B. Mynors, C. Plini Caecili Secundi, Epistularum libri decem, Oxford: Clarendon Press, OCT,1963
- R. A. B. Mynors, Catalogue of the Manuscripts of Balliol College Oxford, Oxford: Clarendon Press, 1963.
- R.A.B. Mynors, XII Panegyrici Latini, Oxford: Clarendon Press, OCT, 1964.
- R.A.B. Mynors, P. Vergili Maronis Opera, Oxford: Clarendon Press, OCT, 1969.
- R. A. B. Mynors, with Bertram Colgrave, Bede's Ecclesiastical history of the English People, Oxford: Clarendon Press, 1969.
- R. A. B. Mynors, Collected Works of Erasmus vols 1-9: The Correspondence: Toronto, Buffalo, London: Toronto University Press, 1974-89 (vols 1-6 with D. F. S. Thomson).
- R.A.B. Mynors (post.: with a pref. by R.G.M. Nisbet), Virgil Georgics, edited with a commentary by R.A.B. M., Oxford: Clarendon Press, 1990.
- R. A. B. Mynors (post.) and R. M. Thomson, Catalogue of the Manuscripts of Hereford Cathedral Library (Cambridge, 1993).
- Summer Fields Register 1864–1960, Oxonian Press, 1960.
- Cyril Connolly, Enemies of Promise, 1938.
- Roger Mynors, Classical Scholar, 86, New York Times, 20 October. 1989.
- The above and much more can be found in the elegant Memoir by M. Winterbottom, Proceedings of the British Academy 80 (1991), 371-401, including a complete list of Mynors' publications.