The Ontario Liberal Party (OLP; , PLO) is a provincial political party in Ontario, Canada. It has been one of the two main contenders for government for much of Ontario's history along with their conservative rival (currently the Progressive Conservative Party). Liberal ministries governed the province 63 of the approximately 160 years since Confederation, producing 10 of its 26 premiers.
The party has strong informal ties to the Liberal Party of Canada, but the two parties are organizationally independent and have separate, though overlapping, memberships. The provincial party and the Ontario wing of the federal party were organizationally one entity until members voted to split in 1976.
The party espouses the principles of liberalism, with their rival the Progressive Conservative (PC) Party positioned to the right and the New Democratic Party (NDP), which at times aligned itself with the Liberals during minority governments, positioned to their left.
The Liberals suffered its worst electoral defeat in the 2018 Ontario provincial election both in terms of seat count (seven) and popular vote (19.6%), losing official party status at the Legislative Assembly of Ontario. It was also the worst defeat of a governing party in Ontario history. Prior to the 2018 election, the party had won four consecutive elections since the turn of the century and had governed the province for the previous 15 years. In the 2022 provincial election, the Liberals saw a modest increase in support, finishing second in popular vote, but only winning eight seats.
In the most recent election in 2025, the party led by Bonnie Crombie won 14 seats and regained official party status. However, Crombie did not win her own seat and the Liberals remained the third-party in the legislature, despite having won a substantially larger share of the popular vote than the official opposition NDP (30% vs NDP's 18.6%).
History Following Ontario's first ministry post Confederation (a predominately Conservative ministry led by a Liberal being opposed by the majority of the Liberals in the first legislative assembly), the Ontario Liberals went through an extended period of dominance, governing the province for 34 of the 50 years between Confederation and World War I. Sir Oliver Mowat, one of the Fathers of Confederation, led the party and the province for 24 of those years, and remains the province's longest-serving premier (and the third longest of any first minister in Canada).
It however spent much of the following century in the wilderness. Bitter internal division ended a nine-year Liberal government in 1943 and produced the province's shortest-serving premier to date in Harry Nixon. Follow four decades in opposition, David Peterson with the support of the NDP ended 42 consecutive years of Progressive Conservative rules in 1985, and led the province for five years. After the turn of the millennium, Dalton McGuinty led the party back to government in 2003. Kathleen Wynne, a minister in the McGuinty ministry, won the party's leadership in 2013, becoming the first woman to serve as Premier of Ontario, and the first openly gay person to serve as first minister anywhere in Canada. She led the party to its most recent victory in 2014, before leading it to its historic defeat in 2018.
Origins The Liberal Party of Ontario is descended from the Reform Party of Robert Baldwin and William Lyon Mackenzie, who argued for responsible government in the 1830s and 1840s against the conservative patrician rule of the Family Compact.
The modern Liberals were founded by George Brown, who sought to rebuild the Reform Party after its collapse in 1854. In 1857, Brown brought together the Reformers and the radical "Clear Grits" of southwestern Ontario to create a new party in Upper Canada with a platform of democratic reform and annexation of the north-west. The party adopted a position in favour of uniting Britain's North American colonies, a concept that led to Canadian Confederation.
Confederation After 1867, Edward Blake became leader of the Ontario Liberal Party. The party sat in opposition to the Conservative government led by John Sandfield Macdonald. Blake's Liberals defeated the Tories in 1871, but Blake left Queen's Park for Ottawa the next year, leaving the provincial Liberals in the hands of Oliver Mowat. Mowat served as Premier of Ontario until 1896.
While the Tories became a narrow, sectarian Protestant party with a base in the Orange Order, the Liberals under Mowat attempted to bring together Catholics and Protestants, rural and urban interests under moderate, religiously liberal leadership.
Decline and opposition The Liberals were defeated in 1905 after over thirty years in power. The party had grown tired and arrogant in government and became increasingly cautious. As well, a growing anti-Catholic sectarian sentiment hurt the Liberals, particularly in Toronto where they were unable to win a seat from 1890 until 1916. The Liberals continued to decline after losing power, and, for a time, were eclipsed by the United Farmers of Ontario (UFO) when the Liberals were unable to attract the growing farmers' protest movement to its ranks.
Debates over the party's policy on liquor divided the membership, forced the resignation of at least one leader, Hartley Dewart, and drove away many reform-minded Liberals who supported the federal party under William Lyon Mackenzie King but found the provincial party too narrow and conservative to support. The party was so disorganized that it was led for seven years (and through two provincial elections) by an interim leader, W.E.N. Sinclair, as there was not enough money or a sufficient level of organization, and too many divisions within the party to hold a leadership convention. By 1930, the Liberals were reduced to a small, rural and prohibitionist rump with a base in south western Ontario.
Return to power under Mitch Hepburn After a series of ineffective leaders, the Liberals turned to Mitchell Hepburn, an onion farmer, federal Member of Parliament and former member of the UFO. Hepburn was able to build an electoral coalition with Liberal-Progressives and attract reformers and urban voters to the party. The Liberal-Progressives had previously supported the UFO and the Progressive Party of Canada. A "wet", Hepburn was able to end the divisions in the party around the issue of temperance which had reduced it to a narrow sect. The revitalized party was able to win votes from rural farmers, particularly in southwestern Ontario, urban Ontario, Catholics and francophones. It also had the advantage of not being in power at the onset of the Great Depression. With the economy in crisis, Ontarians looked for a new government, and Hepburn's populism was able to excite the province.
In government, Hepburn's Liberals warred with organized labour led by the Congress of Industrial Organizations, who were trying to unionize the auto-sector. Later, he battled with the federal Liberal Party of Canada government of William Lyon Mackenzie King, which, Hepburn argued, was insufficiently supportive of the war effort. The battle between Hepburn and King split the Ontario Liberal Party and led to Hepburn's ouster as leader. It also contributed to the party's defeat in the 1943 election, which was followed by the party's long stint in opposition. The Liberals declined to a right wing, rural rump. The "Progressive Conservatives" under George Drew established a dynasty which was to rule Ontario for the next 42 years.
Opposition during the post-war boom Ontario politics in recent times have been dominated by the Progressive Conservatives, also known as the Tories. The Liberals had formed the Government for only five years out of sixty years from 1943 to 2003. For forty-two years, from 1943 to 1985, the province was governed by the Tories. During this period, the Ontario Liberal Party was a rural, conservative rump with a southwestern Ontario base, and were often further to the right of the moderate Red Tory Conservative administrations. In 1964, the party changed their name from the "Ontario Liberal Association" to the "Liberal Party of Ontario".
In September 1964, the party elected Andy Thompson as its leader. While the leadership election garnered some attention, it looked like Thompson would have a hard time winning an election. The Liberals had held office only three times for 13 years since 1900 and the party caucus was not that much different from the time between 1959 and 1963. They failed to get a popular candidate, Charles Templeton, elected in a by-election. They also lost another riding to the PCs when Maurice Bélanger died in March 1964. Thompson would last only two years as leader before resigning due to stress-induced health problems.
Throughout the 1960s and 1970s, the Liberals were almost shut out of Metropolitan Toronto and other urban areas and, in 1975, fell to third place behind the Ontario New Democratic Party (NDP) under Stephen Lewis. With the NDP in ascendancy in the late 1960s and 1970s, it appeared that the Liberals could disappear altogether.
The Liberals remained more popular than the Tories among Catholic and Francophone voters, due to the party's support for extending separate school funding to include Grades 11–13. The Tories opposed this extension until 1985, when they suddenly reversed their position. This reversal angered traditional Conservative voters, and may have contributed to their defeat in the 1985 election.
The Peterson years
The Ontario Liberal Party first broke the Tories' hold on the province in 1985 under the leadership of David Peterson. Peterson modernized the party and made it appealing to urban voters and immigrants who had previously supported the cautious government of Tory Premiers John Robarts and William Davis.
Peterson was able to form a minority government from 1985 to 1987 due to an accord signed with the Ontario NDP. Under this accord, the NDP agreed not to trigger an election via a non-confidence vote in exchange for the Liberals implementing certain agreed upon policies and not calling an election for the next two years.
Once the accord expired, an election was called and Peterson won a strong majority government with 95 seats, its most ever.
Peterson's government ruled in a time of economic plenty where occasional instances of fiscal imprudence were not much remarked on. Peterson was a close ally of Prime Minister Brian Mulroney on the Meech Lake Accord, but opposed Mulroney on the issue of free trade.
The majority Liberal government of 1987 to 1990 was less innovative than the previous minority government. The Liberals' increasing conservatism caused many centre-left voters to look at the Ontario NDP and its leader Bob Rae, and consider the social-democratic NDP as an alternative to the Liberals.
The Liberals went into the 1990 election with apparently strong support in the public opinion polls. This support quickly evaporated, however. On the campaign trail, the media reported that the Liberals were met by voters who were angry at going to the polls just three years into the government's mandate. Another negative factor was Peterson's association with Mulroney and the failed Meech Lake Accord attempt at constitutional reform, about which the public felt strongly. The campaign was also poorly run: a mid-campaign proposal to cut the provincial sales tax was a particularly bad blunder. The party had also underestimated the impact of the Patti Starr fundraising scandal, as well as allegations surrounding the Liberal government's links with land developers.