The Rocky Mountain Lacrosse League (RMLL) is a box lacrosse league based in Alberta with three teams in Saskatchewan and, as of 2018, one in Manitoba.

RMLL organizes all senior and junior play in the province.

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.

The RMLL is guaranteed at least one berth in each of the following national championship tournaments.

However, the Calgary Chinooks won the Mann Cup in 1914.