Ali Abdullah Al-Daffa (Arabic: علي بن عبدالله الدفـّاع) (born 1943 (1362 H) in Unaizah, Al Gassim, Saudi Arabia) is a mathematician, scientist, author, professor, and expert on the history of science and Islam. He obtained his Bachelor of Science degree from Stephen F. Austin State University in 1967, his Master of Science degree from East Texas State University in 1968, and his PhD from Peabody College of Vanderbilt University in 1972. Al-Daffa’ is a Founding Fellow of the "Islamic World Academy of Sciences (IAS)" (1986).