The Ontario Junior Hockey League (OJHL) is a Junior A ice hockey league in Ontario, Canada. It is under the supervision of the Ontario Hockey Association and the Canadian Junior Hockey League. The league dates back to 1954 as the Central Junior B Hockey League. In 1993, the Central Junior B Hockey League was promoted to the Junior A level and renamed the Ontario Provincial Junior A Hockey League. In 2009, the league was dissolved by the Ontario Hockey Association and split into two leagues: the Central Canadian Hockey League and the Ontario Junior A Hockey League. By early 2010, the two leagues merged to reform the Ontario Junior Hockey League.

In July 2013, the TheHockeyWriters.com listed the OJHL as the 7th best developmental league, professional or amateur, in North America.

At its peak, the league was composed of 37 teams and is now mostly based in the Greater Toronto Area with a few teams eastward towards Kingston. The exception to this is the Buffalo Jr. Sabres located in the American state of New York.

The winner of the OJHL playoffs and Frank L. Buckland Trophy compete for the Dudley Hewitt Cup with the winners of the Northern Ontario Junior Hockey League, Superior International Junior Hockey League and the host team. The winner of the Dudley Hewitt Cup then goes on to compete for the Centennial Cup, the national Junior A championship.