The 2004–05 OHL season was the 25th season of the Ontario Hockey League. The OHL inaugurated two awards for scholastic achievement, the Roger Neilson Memorial Award and the Ivan Tennant Memorial Award. Twenty teams each played 68 games. The London Knights set a Canadian Hockey League record, being undefeated in 31 games. On March 11, 2005, the league announced OHL Live Stream, a new streaming service to be developed over a three year period. The J. Ross Robertson Cup was won by the London Knights, defeating the Ottawa 67's.

Regular season

Final standings

Note: DIV = Division; GP = Games played; W = Wins; L = Losses; T = Ties; OTL = Overtime losses; GF = Goals for; GA = Goals against; PTS = Points; x = clinched playoff berth; y = clinched division title; z = clinched conference title

Eastern conference

Western conference

Scoring leaders

Playoffs

Conference quarterfinals

Eastern conference

Western conference

Conference semifinals

Conference finals

J. Ross Robertson Cup finals

J. Ross Robertson Cup Champions Roster

All-Star teams

First team

Second team

Third team

CHL Canada/Russia Series

In the ADT Canada-Russia Challenge: After these two games, OHL had an all-time record of 4–0 against the Russian Selects since the tournament began in 2003–04.

Awards

London Knights' 2004–05 undefeated streak

In the 2004–05 season the London Knights broke an OHL record, going 28 games in a row without a loss (27–0–1). They subsequently broke the CHL record of 29 games (held by the 1978–79 Brandon Wheat Kings, who went 25–0–4 during their streak), with a 0–0 tie with the Guelph Storm on December 10, 2004, giving them a record of 28–0–2. The streak ended at 31 games after a 5–2 loss to the Sudbury Wolves on December 17.

• Tied OHL record previously set by Kitchener in 1983–84 ** Broke OHL record previously set by Kitchener in 1983–84 *** Tied CHL record previously set by Brandon in 1978–79 **** Broke CHL record previously set by Brandon in 1978–79

2005 OHL Priority Selection

On May 7, 2005, the OHL conducted the 2005 Ontario Hockey League Priority Selection. The Oshawa Generals held the first overall pick in the draft, and selected John Tavares from the Toronto Marlboros. Tavares was awarded the Jack Ferguson Award, awarded to the top pick in the draft. Below are the players who were selected in the first round of the 2005 Ontario Hockey League Priority Selection.

2005 CHL Import Draft

On June 29, 2005, the Canadian Hockey League conducted the 2005 CHL Import Draft, in which teams in all three CHL leagues participate in. The Ottawa 67's held the first pick in the draft by a team in the OHL, and selected Jakub Vojta from the Czech Republic with their selection. Below are the players who were selected in the first round by Ontario Hockey League teams in the 2005 CHL Import Draft.