John Duncan Martin Derrett was Professor of Oriental Laws at the University of London, from 1965 to 1982, and afterwards Emeritus Professor.

Derrett was educated at Emanuel School, London, Jesus College, Oxford and the School of Oriental and African Studies, London, before studying law at the Inns of Court School, London. He was called to the bar, Gray's Inn, in 1953. He is the author of a number of works on law and the history of systems of law, India, religion (particularly Christianity) and comparative religion. In his later life he was particularly interested in comparisons of Christianity with Buddhism. Derrett also translated works by others into English.