Origins League1 Ontario was founded on November 15, 2013, in an announcement by the
Ontario Soccer Association (OSA) that it would pilot the
semi-professional league in 2014 and 2015 as a key pillar of long-term player development in Canada. The league would be administered by DG Sports, who also operate the province's amateur
Ontario Soccer League, with Dino Rossi serving as commissioner. OSA President Ron Smale stated that the league's core group of players are to consist of U-23s, with League1 complementing the newly formed Ontario Player Development League (OPDL) elite youth league as a pathway for professional player development. On April 8, 2014, the OSA revealed its plans for the
inaugural season of League1 which would begin during the final weekend in May 2014. The season featured 10 teams, chosen through a standards-based application process, which were:
ANB Futbol,
Durham Power FC,
Internacional de Toronto,
Kingston Cataraqui Clippers,
Master's FA,
Sigma FC,
Toronto FC Academy,
Vaughan Azzurri,
Windsor Stars and
Woodbridge Strikers. The league champion would face the champion of the
Première ligue de soccer du Québec in the
Inter-Provincial Cup to determine the national Division III champion.
Dylan Sacramento of Toronto FC Academy scored the first ever goal in the league with a 10th-minute strike against Vaughan Azzurri. In the same game,
Mateo Restrepo received the league's first red card. with league matches rescheduled for the season to accommodate the change. Toronto FC Academy were crowned the inaugural league champions on October 4, 2014, after defeating the Cataraqui Clippers 3–1 to secure the top place in the regular season standings. Vaughan Azzurri and Sigma FC contested the inaugural League1 Cup on October 19, 2014, at
BMO Field, with the Azzurri winning the single-game cup final 2–1 to be crowned champions. As the number of teams in the league continued to grow through expansion, the league introduced a two-conference format with the winner of each conference facing off in a championship match. After the 2016 season, the Inter-Provincial Cup was cancelled, with the winners of League1 Ontario and the PLSQ instead advancing to the national
Canadian Championship the following season, beginning in 2018. In 2018, the league returned to a single division, introducing playoffs for the top finishers of the league to decide the league champion. The League Cup tournament was eliminated the following season. On November 14, 2018, the
Canadian Premier League announced its purchase of League1 Ontario. According to L1O commissioner Dino Rossi, L1O would serve as "CPL's official development league." Due to restrictions associated with the
COVID-19 pandemic, the league cancelled the
2020 season and delayed the start of the 2021 season. In 2022, L1O joined
League1 Canada as a founding member. League1 Canada is an alliance of soccer leagues that operate at the pro-am level.
Reorganization and rebranding In 2024, League1 Ontario restructured from a single league into a three-tier competition. Existing teams were assigned to one of the top-two tiers based on the number of points they
earned in the previous two seasons. The top-tier "League1 Ontario Premier" division included the top 12 teams while the second tier "League1 Ontario Championship" division featured the remaining 10 teams (with expansion to 12 teams in the 2025 season). Along with this, a third tier known as League2 Ontario debuted in 2024 with 24 teams that included existing club B teams and new teams joining the league. League2 was created as an entry point for expansion clubs to the L1O system. Under the reorganization, teams have the ability to move up and down between tiers through a process of
promotion and relegation. The 2024 season also saw the return of the L1 Cup, a
league cup knockout tournament which features teams from all three tiers of the L1O system. In January 2026, the league rebranded as the Ontario Premier League and adopted a new logo. This change coinceded with rebrands to
Premier Soccer Leagues Canada (formerly League1 Canada) and the
Canadian Premier League, to create a unified identity. The three tiers of the Ontario Premier League were renamed to Ontario Premier League 1, Ontario Premier League 2, and Ontario Premier League 3. ==Competition format==