Ronald Stuart McGregor, commonly R. S. McGregor (or Stuart McGregor) (24 October 1929 – 19 August 2013), was a philologist of the Hindi language. Best known as editor of the Oxford Hindi-English Dictionary, a standard reference work published in 1993 after a sustained effort of twenty years, McGregor was a Fellow of Wolfson College and retired as Reader in Hindi at the University of Cambridge.