This page lists the results of leadership elections within the Progressive Conservative Party of Ontario (known as the Conservative Party of Ontario before 1942).

Before 1920, leaders of the Conservative Party were usually chosen by caucus. In 1914, William Hearst was selected at a meeting of the province's executive council (or cabinet) as James Whitney, the previous leader, had died while holding the office of Premier of Ontario.

All of the party's leadership races before 1990 were determined by delegated conventions. The leadership races of 1990, 2002 and 2004 were determined by a weighted vote of all party members, with each constituency contributing an equal number of "votes" to the total. The 1990 race was decided in one round, while the 2002 race took two. For the 2004 election, the party introduced a preferential balloting system, such that party members would only be required to vote one time.

(Held on December 2, 1920.)

• Howard Ferguson won on first ballot
• Earl Lawson
• George Stewart Henry

(Note: The vote totals were not announced.)

When Ferguson resigned as Premier in 1930, he selected George Henry as his replacement. Henry was subsequently confirmed as party leader at a special Meeting on June 24, 1931.^[1]

(Held on May 28, 1936 at the Royal York Hotel in Toronto.)

First ballot:

• Earl Rowe 782
• George A. Drew 480
• William James Stewart 157
• Leopold Macaulay 90
• Wilfrid Heighington 70
• Adam Acres 47
• Arthur Ellis 10

Second ballot:

• Earl Rowe 1,005
• George A. Drew 660

(Held on December 9, 1938, at the Royal York Hotel in Toronto.)

• George A. Drew 796
• Earl Lawson 413
• Wilfrid Heighington 41
• Norman Rawson 22

(Held on April 27, 1949.)

• Leslie Frost 842
• Leslie Blackwell 442
• Kelso Roberts 121
• Dana Porter 65

(Held on October 25, 1961.)

(Held on February 12, 1971.)

(Held in Toronto on January 26, 1985.)

First ballot:

• Frank Miller 591
• Dennis Timbrell 421
• Larry Grossman 378
• Roy McMurtry 300

Second ballot (McMurtry supports Grossman):

• Frank Miller 659
• Larry Grossman 514
• Dennis Timbrell 508

(Note: These figures were confirmed by a recount.)

Third ballot (Timbrell supports Grossman):

• Frank Miller 869
• Larry Grossman 792

(Held on November 16, 1985.)

First ballot:

• Larry Grossman 752
• Dennis Timbrell 661
• Alan Pope 271

Second ballot:

• Larry Grossman 848
• Dennis Timbrell 829

(Held on May 12, 1990.)

• Mike Harris 7,175
• Dianne Cunningham 5,825

(the non-weighted vote totals were: Harris 8,661, Cunningham 7,189)

The 1990 vote was the first held on the basis of one member one vote with votes weighted so that each riding had equal weight.

(Held on March 23, 2002.)

First ballot:

• Ernie Eves 4,257
• Jim Flaherty 3,031
• Tony Clement 1,354
• Elizabeth Witmer 1,197
• Chris Stockwell 448

(Note: After the first ballot, Clement and Witmer both withdrew from the contest and supported Ernie Eves. Their names remained on the ballot for at least a part of the second round, however.)

Second ballot:

• Ernie Eves 5,623
• Jim Flaherty 3,898
• Tony Clement 561
• Elizabeth Witmer 216

(It is not clear if the non-weighted vote totals were released to the public. 44188 party members voted on the first ballot, 34,608 on the second.)

(Held on September 18, 2004.)

First ballot:

• John Tory 4,535.13 (45%)
• Jim Flaherty 3,274.92 (33%)
• Frank Klees 2,265.96 (22%)

5,039 electoral votes needed to win

(the non-weighted vote totals were Tory 12,132, Flaherty 7,951, Klees 5,240)

Second ballot:

• John Tory 5,390.86 (54%)
• Jim Flaherty 4,664.14 (46%)

5,028 electoral votes needed to win

(the non-weighted vote totals were Tory 18,037, Flaherty 14,353)

(Held on June 27, 2009, in Markham, Ontario)

Movement: Hillier eliminated and endorses Hudak; prior to balloting Hillier asked his supporters to make Hudak their second choice.

Does not include votes that were spoiled because no second choice was indicated.

Movement: Elliott eliminated

Does not include votes that were spoiled because no second or third choice was indicated.

(Held in Toronto on May 27, 2015)

(Held on March 10, 2018)

Called due to the resignation of party leader Patrick Brown on January 25, 2018 following allegations of sexual misconduct.^[2]