After the realignment of the Quebec–Ontario Athletic Association, Ontario Intercollegiate Athletic Association and Ottawa-St. Lawrence Conference in 1971, the Ontario University Athletic Association was born. The league began with 14 teams arranged into four divisions .The inaugural postseason tournament invited eight teams with the top four from each division automatically qualifying for the playoffs. The quarterfinal matches were all played within the same division while the semifinals were played cross-division.
Beginning in 1976, the OUAA was divided into three divisions: East, Central and West. The inaugural tournament under this new arrangement was a convoluted affair. The top two teams from each division would make the tournament while the third place team with the best record would also be allowed entry. The team with the best record would receive a bye into the semifinal round, however, there was a slight issue. Because the teams played an unbalanced schedule with the central playing three games against division foes, the east four games and west five, the divisional records were not interchangeable. However, despite this, the OUAA still used the point system to determine the league champion rather than winning percentage. This resulted in Western Ontario receiving a bye while Toronto had the best overall record. The seeding was set up so that the two other division winners were placed in the same semifinal bracket. The two second-place teams with the worst record were set against one another and placed in the bracket with the team that received the bye. Of the remaining two teams, the one with the worst record was set against the second-best division winner. This convoluted process was abandoned after one season and replaced with another that was just as unfathomable. In 1977 the bye was eliminated and instead the best two third place teams would make the tournament. The third place teams were set against the second place teams from their own divisions in the quarterfinal round while the top two division winners were placed on opposite sides of the bracket. In order to reduce travel, the division that did not advance a third place team was separated so that they would play the nearest of the other division winners. This resulted in York and Ryerson (both located in Toronto) being set against one another in the quarterfinal round despite both being division champions. This rather unique arrangement persisted for three seasons before the loss of three conference members caused the league to revert to a single division with six teams making the postseason.
Over the course of a decade, the OUAA began to shift from single-elimination rounds to best-of-three. 1978 saw the final round become a 3-game series with the semifinal following in 1980. It wasn't until the tournament was expanded back to an eight-team bracket in 1987 that the quarterfinal round became best-of-three as well. The following season, The QUAA collapsed and all four teams were absorbed into the OUAA. The league reverted to three divisions and expanded the playoffs to include twelve teams. The format was arranged so that the top four teams in each division would play in their respective division brackets. The winners would advance to the league semifinal along with the losing team with the best record. The first two rounds were best-of-three series while the final two were single-elimination. This setup lasted two years and was altered when McMaster suspended its program. Beginning in 1990, the OUAA switched to two divisions and alternated its postseason between 12- and 8-team formats. The additional first round series were single-elimination while the succeeding round remained best-of-three. Starting in 1992, the championship game was switched to single-elimination.
In 1994, the two 8-team divisions were split and the league was now arranged into four 4-team divisions. The top three teams from each division made the postseason with the division champions advancing to the quarterfinal round. First and second round matches were all played within the divisions and the final four was arranged so that both the eastern and western halves would be represented in the championship game. In this format, only the quarterfinal round was best-of-three with all other round being single-elimination. The OUAA changes its name to Ontario University Athletics (OUA) in 1998.
† Due to an infraction, Western Ontario was deducted several points in the standings. The type of violation and the severity of the punishment is not currently available.
