The Ontario Junior B Lacrosse League (OJBLL) is a box lacrosse league sanctioned by the Ontario Lacrosse Association in Canada. The league features twenty-five teams in Ontario, one in Quebec, and one in the Akwesasne (which straddles the two aforementioned provinces and New York) that annually play a 20-game schedule and four rounds of playoffs for the J. A. MacDonald Trophy. After the conclusion of the playoffs, a league champion represents the OJBLL at the Founders Cup National Junior B Championship.