William P. Leahy, SJ (born 1948) is the 25th President of Boston College, a post he has held since 1996. He was born in Omaha, Nebraska and raised in Imogene, Iowa, he joined the Society of Jesus in 1967, and is a member of the Jesuit's Wisconsin province. Leahy earned a bachelor's degree in philosophy and a master's degree in United States history at Saint Louis University in 1972 and 1975, respectively. He then began studies at the Jesuit School of Theology in Berkeley, California, where he earned degrees in theology (1978) and historical theology (1980). He received a doctoral degree in US history from Stanford University in 1986.

He began his academic career as a teacher at Campion Jesuit High School in Wisconsin from 1973-1975. He served as a teaching assistant at Stanford in 1981 before joining the Marquette University faculty as an instructor of history in 1985. He became an associate professor with tenure in 1991, and in that same year became Marquette's executive vice president.