The Minto Cup is awarded annually to the champion junior men's lacrosse team of Canada.
It was donated in 1901 by the Governor-General, Lord Minto. Originally restricted to amateurs, within three years the first under-the-table professional teams were already competing for it. After 1904, with efforts to keep the professionals out of competition proving to be futile, it was made open to all challengers.
The last successful amateur challenge came in 1908 when New Westminster Salmonbellies won it; the last amateur challenge was made in 1913 by Vancouver Athletic Club. This would be the only time in Canadian lacrosse history when the Mann Cup champions (Vancouver) faced the Minto Cup champions (New Westminster) head-to-head – with the silverware (Minto) going to the winner.
With the professionals essentially in control of the cup by 1910, the newly inaugurated Mann Cup became the replacement for the senior men's national amateur championship.
The Minto Cup professional competition was dominated by the New Westminster Salmonbellies, who held the trophy for 21 of the 29 years in which it was contested (the competition was suspended during World War I). 1924 was the last year professionals played for the Minto Cup—after the Coast professional league folded in June 1924, it was then placed into storage and for a time lost and forgotten when the last trustee died. The trophy was located just prior to the 1938 junior competition, underneath a desk in his office. During the trophy's period of inactivity, there were suggestions to make the Minto Cup an international championship trophy.
In 1934 the last trustee appointed to supervise the Cup died, and the Lord Minto of the day eventually transferred it to the Canadian Lacrosse Association, which decided to award it as the trophy for the national junior men's champion, starting in 1937. Originally, the competition was between all-star provincial teams formed by adding players to the provincial champion. In 1960 this practice was abandoned and the trophy has since been competed for by the Junior A provincial champions of British Columbia of the British Columbia Junior A Lacrosse League, Ontario of the Ontario Junior A Lacrosse League and recently Alberta, of the RMLL the only provinces where organized lacrosse thrives.