Mark Gregory Pegg (born 1963) is an Australian professor of medieval history, currently teaching in the United States at Washington University in St. Louis, Missouri.
Apart from these specific scholarly pursuits, he writes more broadly about what shapes and defines the medieval West from 200 to 1500.
He is the author of The Corruption of Angels: The Great Inquisition of 1245–1246, A Most Holy War: The Albigensian Crusade and the Battle for Christendom, and Beatrice's Last Smile: A New History of the Middle Ages.
He received his master's degree (1993) and Ph.D. (1997) from Princeton University, where his dissertation advisor was William Chester Jordan.
Pegg publishes widely on the crusades, heresy, the inquisition, and the Middle Ages generally.