The ACH Senior AA G-League is the working name of a Senior AA men's ice hockey league that begins play with the 2021-22 playing season. The league is being developed by Allan Cup Hockey and is under the sanction of Hockey Canada, the Ontario Hockey Federation and the Ontario Hockey Association. Due to the league's Senior AA status it will not be eligible to compete for the Allan Cup.
On June 14, 2021 the league issued a release stating that it was starting a Senior AA league (tentatively called the ACH Senior AA G-League, after the National Basketball Association's developmental G League) for players aged 21 to 28. The new league had already been approved by the Ontario Hockey Association and the Ontario Hockey Federation. The league grew out of the lost 2020-21 playing season as many 20 year olds lost their final year of junior hockey and were left with few options for competitive hockey outside of Canadian university of American collegiate leagues. The major eligibility difference with ACH will be that the new league will not permit ex-pro players. The primary focus for the league will be players from the Ontario Junior Hockey League, Greater Ontario Junior Hockey League and the Provincial Junior Hockey League (OHA).
The league will also fill a void for lower level senior hockey in the Golden Horseshoe region as there is no other Senior AA level league covering the area. There are three other senior leagues in the province for 2021-22 as the Western Ontario Super Hockey League begins play being based out of southwestern Ontario, the Eastern Ontario Super Hockey League fills most of the area covered by Hockey Eastern Ontario and the area east of Greater Toronto Area, and the WOAA Senior AA Hockey League plays in the area east of Lake Huron and southwestern Ontario west of the Golden Horseshoe region.
- Paris Mounties - Owner of team announced transition from a junior C team to a senior AA team on June 21, 2021.
- Hamilton Henchmen - Announced on June 28, 2021. The team is owned by the owners of the Dundas Blues and the Hamilton Kilty B's (2018-).
More teams to be announced