Brian Tierney (May 7, 1922 – November 30, 2019) was an English historian and medievalist. He was a member of the faculty of the Catholic University of America for eight years until becoming a professor of medieval history at Cornell University in 1959, where he was later appointed as the Goldwin Smith Professor of Medieval History in 1969 and the first Bowmar Professor of Humanistic Studies in 1977.

His speciality was medieval church history, focusing on the structure of the medieval church and the medieval state, and the influences of the interaction between these on the development of Western institutions. [Source: Wikipedia]