James Douglas Howard-Johnston (born 12 March 1942), is an English historian of the Byzantine Empire. He was University Lecturer in Byzantine Studies at the University of Oxford. He is an emeritus fellow of Corpus Christi College, Oxford. His approach on Byzantium follows that of Edward Gibbon and concentrates on comparisons between the Byzantine state and its Western counterparts. Also, Howard-Johnston has done much research on Late Antiquity, especially the Roman-Persian Wars and the Coming of Islam. He is married to the novelist Angela Huth.
- "Witnesses to a World Crisis: Historians and Histories of the Middle East in the Seventh Century". (2010)
- "The cult of saints in late antiquity and the Middle Ages: essays on the contribution of Peter Brown." (1999)
- "The scholar & the gypsy: two journeys to Turkey" – Past and Present. (1992)
- "Studies in the organization of the Byzantine army in the tenth and eleventh centuries". (1971)