The Marshall League is composed of 16 senior men's teams, and is broken down into two divisions: the Marshall Premiership and the Marshall Championship.
The Marshall Premiership is made up of the top eight clubs in Ontario (outside of the EORU), based on the results of the 2013 league. These clubs are: Aurora Barbarians, Balmy Beach, Brantford Harlequins, Markham Irish, Oakville Crusaders, Stoney Creek, Toronto Scottish, and Waterloo County.
The Marshall Championship division serves as Ontario's second division, and is made up of: Ajax Wanderers, Barrie, Brampton Beavers, Lindsay, London St. George's, Oshawa Vikings, Peterborough Pagans, and Sarnia Saints.
Each club in the Marshall League will field both 1st and 2nd XV for the duration of the season. Clubs will have the option of running a 3rd XV team, either playing in Branch leagues or playing exhibition games against other 3rd XV teams.
At the end of the season, the 8th-place team in the Marshall Premiership will be relegated to the Marshall Championship, while the winner of the Marshall Championship will earn promotion to the Marshall Premiership.
The 8th-place team of the Marshall Championship will participate in the Men’s Intermediate Cup against the top teams from NRU and TRU Branch leagues for a chance to retain their position in the Marshall Championship in 2015.