The 1955 Ontario general election was held on June 9, 1955, to elect the 98 members of the 25th Legislative Assembly of Ontario (Members of Provincial Parliament, or "MPPs") of the Province of Ontario. The Ontario Progressive Conservative Party, led by Leslie Frost, won a fifth consecutive term in office, increasing its caucus in the legislature from 79 in the previous election to 83. The Ontario Liberal Party, again led by Farquhar Oliver, won three additional seats in the enlarged legislature, increasing its caucus from 8 to 11, and continuing in the role of official opposition. Liberal-Labour MPP Albert Wren was re-elected and continued to sit with the Liberal caucus. The social democratic Co-operative Commonwealth Federation (CCF), led by Donald C. MacDonald, won one additional seat, for a total of three. The Labor-Progressive Party (which was the Communist Party) lost its last remaining seat with the defeat of J.B. Salsberg. James Shannon Dempsey (Renfrew South) had his endorsement as a PC candidate withdrawn because of controversy over a political gift, but he was reelected as an Independent PC.

Pre-election developments

Franchise reform

The Election Act, 1951 was significantly amended in 1954, providing for the following changes to the right to vote in Ontario:

Expansion of Legislative Assembly

For the first time since the 1934 election, the number of seats in the Legislature was adjusted, rising from 90 to 98. The following changes were made:

Campaign

Results

! colspan=2 rowspan=2 | Political party ! rowspan=2 | Party leader ! colspan=5 | MPPs ! colspan=3 | Votes ! Candidates ! Dissol. !1955 !± !# !% ! ± (pp)

Synopsis of results

Analysis

Reorganization of ridings

The reorganized ridings returned the following MLAs: