The Mimico Junior A Mountaineers are a Jr. A box lacrosse association in Toronto, Ontario, Canada.

[1] 1993-: Since the expansion in 1993 with the Nepean Knights, the Mimico Mountaineers never really wavered from "average", and lacked consistency between 1993 and 2000.

Between 2001 and 2010 there had been noticeable improvement, but ultimately even during this time of success the Mountaineers found themselves bowing out in the early stages of the playoffs.

2014: On June 26, 2014 the Jr. B Mountaineers amalgamated with the Mississauga Tomahawks of the Ontario Junior A Lacrosse League.

This is a huge step for the Mountaineers organization, who won 12 of their 20 regular season games, including an 8-2 home record.