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.