The 1st Parliament of Ontario was in session from September 3, 1867, until February 25, 1871, just prior to the 1871 general election. This was the first session of the Legislature after Confederation succeeding the Legislative Assembly of the Province of Canada. The 1867 general election produced a tie between the Conservative Party led by John Sandfield Macdonald and the Liberal Party led by Archibald McKellar. Macdonald led a coalition government with the support of moderate Liberals.
The Second Parliament of Ontario was in session from March 21, 1871, until December 23, 1874, just prior to the 1875 general election. The majority party was the Ontario Liberal Party led by Edward Blake; Oliver Mowat replaced Blake as premier in October 1872. An act was passed in 1872 which prohibited a member from holding a seat in the Legislative Assembly while holding a seat in the Dominion Parliament, a so-called "dual mandate". There were 88 members in the second legislature.
The 5th Parliament of Ontario was in session from February 27, 1883, until November 15, 1886, just prior to the 1886 general election. The majority party was the Ontario Liberal Party led by Oliver Mowat.
The 4th Parliament of Ontario was in session from June 5, 1879, until February 1, 1883, just prior to the 1883 general election. The majority party was the Liberal Party led by Oliver Mowat.
The 6th Parliament of Ontario was in session from December 29, 1886, until April 26, 1890, just prior to the 1890 general election. The majority party was the Ontario Liberal Party led by Oliver Mowat.
The 7th Legislative Assembly of Ontario was in session from June 5, 1890, until May 29, 1894, just prior to the 1894 general election. The majority party was the Ontario Liberal Party led by Oliver Mowat.
The 8th Legislative Assembly of Ontario was in session from June 26, 1894, until January 28, 1898, just prior to the 1898 general election. The majority party was the Ontario Liberal Party led by Oliver Mowat. Arthur Sturgis Hardy succeeded Mowat as Premier in 1896 after Mowat entered federal politics. The Assembly also had significant groupings from the Patrons of Industry and the Protestant Protective Association, each of which returned candidates either on their own or with local Liberal or Conservative support.
The 9th Legislative Assembly of Ontario was in session from March 1, 1898, until April 19, 1902, just prior to the 1902 general election. The majority party was the Ontario Liberal Party led by Arthur Sturgis Hardy. George William Ross became the Liberal leader when Hardy retired in 1899.
The 10th Legislative Assembly of Ontario was in session from May 29, 1902, until December 13, 1904, just prior to the 1905 general election. The majority party was the Ontario Liberal Party led by George William Ross.
The 13th Legislative Assembly of Ontario was in session from December 11, 1911, until May 29, 1914, just prior to the 1914 general election. The majority party was the Ontario Conservative Party led by Sir James P. Whitney.
The 14th Legislative Assembly of Ontario was in session from June 29, 1914, until September 23, 1919, just prior to the 1919 general election. The majority party was the Ontario Conservative Party led by Sir James P. Whitney.
The 16th Legislative Assembly of Ontario was in session from June 25, 1923, until October 18, 1926, just prior to the 1926 general election. The majority party was the Ontario Conservative Party led by George Howard Ferguson.
The 22nd Legislative Assembly of Ontario was in session from June 4, 1945, until April 27, 1948, just prior to the 1948 general election. The majority party was the Ontario Progressive Conservative Party led by George Drew.
The 25th Legislative Assembly of Ontario was in session from June 9, 1955, until May 4, 1959, just prior to the 1959 general election. The majority party was the Ontario Progressive Conservative Party led by Leslie Frost.
The 26th Legislative Assembly of Ontario was in session from June 11, 1959, until August 16, 1963, just prior to the 1963 general election. The majority party was the Ontario Progressive Conservative Party led by Leslie Frost.
The 27th Legislative Assembly of Ontario was in session from September 25, 1963, until September 5, 1967, just prior to the 1967 general election. The majority party was the Ontario Progressive Conservative Party led by John Robarts.
The 28th Legislative Assembly of Ontario was in session from October 17, 1967, until September 13, 1971, just prior to the 1971 general election. The majority party was the Ontario Progressive Conservative Party led by John Robarts.
The 29th Legislative Assembly of Ontario was in session from October 21, 1971, until August 11, 1975, just prior to the 1975 general election. The majority party was the Ontario Progressive Conservative Party led by Bill Davis.
The 31st Legislative Assembly of Ontario was in session from June 9, 1977, until February 2, 1981, just prior to the 1981 general election. The Ontario Progressive Conservative Party led by Bill Davis formed a second consecutive minority government.
The 34th Legislative Assembly of Ontario was in session from September 10, 1987, until July 30, 1990, just prior to the 1990 general election. The majority party was the Ontario Liberal Party led by David Peterson.
