List of premiers of Ontario by time in office

This is a list of premiers of Ontario in order of time served in office as premier of Ontario as of December 3, 2024. The preceding premier always stays in office during an election campaign, and that time is included in the total. See also List of Ontario political parties by time in office.

List

Rank	Premier	Incumbency	Dates in office	Mandates	Party
1	Oliver Mowat	23 years, 270 days	1872–1896	6	█ Liberal
2	Bill Davis	13 years, 344 days	1971–1985	4	█ Progressive Conservative
3	Leslie Frost	12 years, 188 days	1949–1961	3	█ Progressive Conservative
4	James Whitney	9 years, 229 days	1905–1914	4	█ Conservative
5	John Robarts	9 years, 113 days	1961–1971	2	█ Progressive Conservative
6	Dalton McGuinty	9 years, 111 days	2003–2013	3	█ Liberal
7	Mitchell Hepburn	8 years, 103 days	1934–1942	2	█ Liberal
8	Howard Ferguson	7 years, 152 days	1923–1930	3	█ Conservative
9	Mike Harris	6 years, 292 days	1995–2002	2	█ Progressive Conservative
10	Doug Ford (incumbent)	6 years, 157 days	2018–present	2	█ Progressive Conservative
11	Kathleen Wynne	5 years, 138 days	2013–2018	1	█ Liberal
12	George William Ross	5 years, 110 days	1899–1905	1	█ Liberal
13	David Peterson	5 years, 97 days	1985–1990	1*	█ Liberal
14	George A. Drew	5 years, 63 days	1943–1948	3	█ Progressive Conservative
15	William Howard Hearst	5 years, 43 days	1914–1919	0	█ Conservative
16	Bob Rae	4 years, 268 days	1990–1995	1	█ New Democratic
17	John Sandfield Macdonald	4 years, 157 days	1867–1871	1	█ Conservative
18	Ernest Charles Drury	3 years, 244 days	1919–1923	1	█ United Farmers
19	George Stewart Henry	3 years, 207 days	1930–1934	0	█ Conservative
20	Arthur Sturgis Hardy	3 years, 92 days	1896–1899	1	█ Liberal
21	Ernie Eves	1 year, 190 days	2002–2003	0	█ Progressive Conservative
22	Edward Blake	310 days	1871–1872	1	█ Liberal
23	Gordon Daniel Conant	209 days	1942–1943	0	█ Liberal
24	Thomas Laird Kennedy	197 days	1948-1949	0	█ Progressive Conservative
25	Frank Miller	138 days	1985	1*	█ Progressive Conservative
26	Harry Nixon	91 days	1943	0	█ Liberal

^* Frank Miller's Progressive Conservative Party won a plurality of seats in the 1985 Ontario general election, but the resulting 33rd Parliament of Ontario passed a motion of no confidence against him less than two months into his mandate, replacing his government with David Peterson's Liberal Party. This table counts the 1985 election as a mandate for Miller.