William G. Tierney (born September 26, 1952) is an American lacrosse coach who currently heads the men's lacrosse team at the University of Denver. Tierney is the first college lacrosse coach to win an NCAA DI Championship west of the Eastern Time Zone. He has coached seven NCAA DI championship teams, including six at Princeton University and one at the University of Denver. Tierney's teams have had a combined winning percentage of .750.
