The 1975 Ontario general election was held on September 18, 1975, to elect the 125 members of the 30th Legislative Assembly of Ontario (Members of Provincial Parliament, or "MPPs") of the Province of Ontario, Canada. The Ontario Progressive Conservative Party, led by Bill Davis and campaigning under the slogan, "Your Future. Your choice.", won a tenth consecutive term in office but lost its majority in the legislature for the first time since the 1945 election. The PC party lost 27 seats from its result in the previous election. The social democratic Ontario New Democratic Party, led by Stephen Lewis with the slogan "Tomorrow starts today", doubled its representation in the legislature, and became the Official Opposition on the strength of a campaign which called for rent control in Ontario and highlighted horror stories of individuals victimized by bad landlords who imposed exorbitant rent increases. The campaign forced Davis' Tories to promise to implement rent controls shortly before the election. The Ontario Liberal Party, led by Robert Nixon, won 16 additional seats, but lost the role of Official Opposition to the NDP. One member of its caucus was elected as a Liberal-Labour candidate.

Expansion of Legislative Assembly

An Act passed in May 1975 provided for an increase from 117 to 125 MPPs in the next Assembly:

Campaign

Among the independent candidates, there were 12 from the Social Credit League of Ontario who were not officially recognized as such as the party did not qualify for official party status under the Election Finances Reform Act, 1975.

Opinion polls

Results

Summary

! colspan=2 rowspan=2 | Political party ! rowspan=2 | Party leader ! colspan=4 | MPPs ! colspan=4 | Votes ! Candidates !1975 !± !# ! ± !% ! ± (pp) ! colspan="3" style="text-align:left;" | Total ! " colspan="2"|125 ! " colspan="2"|3,306,397 ! " colspan="2"| 100.00%

Synopsis of results

Analysis

MPPs elected by region and riding

Party designations are as follows: {{legend|#9999FF|PC}} {{legend|#EA6D6A|Liberal}} {{legend|#F4A460|NDP}} {{legend|#EEBBBB|Liberal-Labour}}