The Rocky Mountain Lacrosse League (RMLL) is the name of the box lacrosse leagues in Alberta with one team in Saskatchewan and as of 2011 one in Manitoba. It is sanctioned by the Alberta Lacrosse Association. It organizes all senior and junior play in the province. The league is broken into several divisions: Senior B, Junior A, Junior B, Tier II and III junior as well as a Junior Ladies division.
The RMLL is experiencing rapid growth as the popularity of box lacrosse increases, spurred on by the expansion of the National Lacrosse League to Calgary in 2001 and Edmonton in 2005. In 2002, 18 teams played in the RMLL at all levels. In 2005, 37 teams participated. In 2006, 59 teams are competing.