Three Nations Senior Lacrosse League
TNSLL  | |
| Sport | Box lacrosse | 
|---|---|
| Founded | 2009 | 
| No. of teams | 4 | 
| Confederation | First Nations Lacrosse Association | 
| Most recent champion(s)  | Snake Island Muskies  (2023)  | 
| Most titles | Snake Island Muskies (6) | 
| Official website | qslltnsll | 
The Three Nations Senior Lacrosse League (TNSLL) is a Senior B box lacrosse league based out of Ontario, Quebec and New York, sanctioned by the First Nations Lacrosse Association (FNLA). The league champion earns a spot in the Presidents Cup, the national championship of Senior B lacrosse in Canada.