William English "Brit" Kirwan (born April 14, 1938) is an American university administrator and mathematician who is chancellor emeritus of the University System of Maryland (USM) and professor emeritus of mathematics at the University of Maryland, College Park. Most recently, Kirwan served as chancellor of USM from 2002 to 2015. Previously, Kirwan worked at the University of Maryland, College Park from the 1960s to 1990s as a professor, administrator, and eventually president and was president of the Ohio State University from 1998 to 2002.