Major Series Lacrosse, or MSL, is Ontario’s Senior A summer box lacrosse league. Its teams compete for a league championship and the chance to represent Ontario in the Mann Cup, Canada’s national senior box lacrosse championship.

That means the MSL title is not the finish line. Win the league, and another challenge awaits: a national championship series against the Western Lacrosse Association champion.

• Subscribe To FloLacrosse To Watch The NLL
• FloSports, NLL Announce Exclusive Multiyear Global Streaming Partnership
• Box Lacrosse On FloLacrosse: 10 AWESOME Things To Know About The NLL

For new viewers, the appeal goes beyond learning another league’s initials. MSL combines recognizable box lacrosse names, community-based clubs and a championship chase that the Six Nations Chiefs have dominated, winning four consecutive league titles and Mann Cups from 2023 through 2026.

What Does Senior A Mean In Lacrosse?

Senior A is the top adult-level classification in Ontario’s domestic box lacrosse system. MSL operates under the Ontario Lacrosse Association.

The designation describes the level of competition, not a standard salary or a guarantee that every player is a paid professional. MSL includes players with National Lacrosse League experience, but it is a separate competition with its own teams and championship.

Which Teams Play In Major Series Lacrosse?

Seven Ontario teams competed in the 2026 MSL season. Their home arenas were:

• Brampton Excelsiors: Brampton Memorial Arena.
• Brooklin Lacrosse Club: Iroquois Park Sports Centre in Whitby.
• Cobourg Kodiaks: Cobourg Community Centre.
• Oakville Rock: Toronto Rock Athletic Centre.
• Owen Sound North Stars: Harry Lumley Bayshore Community Centre.
• Peterborough Lakers: Peterborough Memorial Centre.
• Six Nations Chiefs: Iroquois Lacrosse Arena.

Those names provide a starting point for choosing a team to follow. Six Nations and Peterborough met in the 2026 championship final, while Oakville and Cobourg also reached the playoffs.

What Are The Basic MSL Rules?

Box lacrosse is played on an enclosed arena floor with boards. Teams normally have six players on the floor: five runners, meaning non-goaltenders, and one goalie.

Under the 2026 MSL rules, regulation consisted of three 20-minute periods, with the clock stopping at whistles and 10-minute intermissions. A 30-second shot clock required teams to take a qualifying shot on goal rather than simply hold possession.

Runners can substitute during live play through the designated team area. Crease violations around the goal can negate a score, and illegal checks, slashing and dangerous conduct are penalized.

For viewers, the compact floor, quick changes and close-range shooting are central to the attraction. An offense has limited time to turn possession into a scoring chance, while a change of possession can quickly send play in the opposite direction.

How Does The MSL Season Work?

In 2026, each team played 18 regular-season games in a single league table. Four teams advanced to the playoffs, with the No. 1 seed facing No. 4 and No. 2 meeting No. 3.

The semifinals were best-of-five series, followed by a best-of-seven championship final. Those details describe the completed 2026 season, rather than a confirmed format for 2027.

The postseason also showed why regular-season seeding is only part of the story. Third-seeded Peterborough eliminated second-seeded Oakville 3-1 before taking Six Nations to six games in the final.

How Does MSL Connect To The Mann Cup?

The MSL champion faces the WLA champion in the Mann Cup, a best-of-seven national championship series. MSL provides Ontario’s representative, while the WLA provides British Columbia’s.

Winning MSL does not automatically make a team the national champion. The league title earns the opportunity to compete for that next trophy.

Six Nations won both in 2026. The Chiefs beat the Peterborough Lakers 4-2 in the MSL final, clinching with a 10-3 victory Aug. 30. They then swept the Coquitlam Adanacs 4-0 in the Mann Cup, finishing with a 10-2 win Sept. 15.

That distinction matters when following championship histories: an MSL title and a Mann Cup are separate accomplishments, even when the same team wins both.

Do NLL Players Play In MSL?

Yes. MSL features players with NLL experience, creating a connection between the summer league and professional box lacrosse. Six Nations’ 2026 participants included Dhane Smith, Josh Byrne and Lyle Thompson.

The connection also extends to draft prospects. Cobourg’s Aaron Toguri won the 2026 MSL rookie of the year award and was selected eighth overall by Saskatchewan in the 2026 NLL draft. A past MSL affiliation, however, does not guarantee a player’s return for another summer.

MSL and the NLL follow different calendars and crown different champions. MSL is also distinct from Major League Lacrosse, the former field lacrosse competition.

How Can Fans Watch Major Series Lacrosse?

FloSports has announced MSL coverage on FloLacrosse. Its five-year exclusive MSL agreement includes regular-season games and league playoffs.

FloLacrosse’s announced lineup also includes the NLL, Arena Lacrosse League and Mann Cup. Check official FloLacrosse event listings for game schedules and viewing information as the next MSL season approaches.

FloLacrosse Archived Footage

Video footage from the event will be archived and stored in a video library for FloLacrosse subscribers to watch for the duration of their subscription.

Join The Lacrosse Conversation On Social

• Follow us on X @flolacrosse.
• Follow us on Instagram @flolacrossetv.
• Watch Us On YouTube.
• Like us on Facebook.