2023 Toronto mayoral by-election

The 2023 Toronto mayoral by-election was held on Monday, June 26, 2023, to elect the 66th mayor of Toronto to serve the remainder of the 2022–2026 city council term following the resignation of Mayor John Tory. The election was won by Olivia Chow, a former city councillor and member of Parliament (MP). She defeated former deputy mayor Ana Bailão, former police chief Mark Saunders, and 99 other candidates. Chow assumed office on July 12, 2023.

On February 10, 2023, Mayor Tory announced his intention to resign following the admission of an affair with a staffer; he left office on February 17, 2023. The deputy mayor, Jennifer McKelvie, assumed certain mayoral powers and was the highest ranking official in the city until a permanent successor was elected. The nomination period for candidates opened on April 3, 2023, closing on May 12, with 102 registered candidates.

Resignation of John Tory and subsequent vacancy
Tory was first elected in the 2014 mayoral election, and was re-elected in 2018 and 2022. On February 10, 2023, the Toronto Star sent a series of questions to the mayor regarding a relationship he had with a female staffer in his office during the COVID-19 pandemic. Tory confirmed the allegations, admitting to making a "serious error in judgement". Later in the day, Tory announced his intention to resign as mayor of Toronto.

Allies of Tory including city councillors Jon Burnside, Frances Nunziata and Gary Crawford had urged him to stay as mayor, and not resign the post. Premier Doug Ford and the Toronto Police Association also encouraged him not to resign.

Following the passage of the budget on February 15, Tory submitted a letter of resignation to the city clerk, to be effective February 17, 2023, at 5p.m. During the vacancy, Deputy Mayor Jennifer McKelvie performed the duties of the mayor's office until a permanent successor was elected.

Polling during the election campaign suggested that Tory would win the election if he was a candidate. Despite stating that he would not endorse a candidate, Tory subsequently endorsed his deputy mayor Ana Bailão.

By-election process
Under the City of Toronto Act, Toronto City Council must declare the office of mayor vacant following Tory's resignation. Within 60 days, a by-law must be passed to set up a by-election. A nomination period for candidates occurs, lasting a minimum of 30 and maximum of 60 days after the formal declaration of a by-election and ends 45 days before the election. The by-election is projected to cost the city approximately $13 million to run. Municipal elections in Toronto are non-partisan, and are held under first-past-the-post voting.

The City Clerk's Office announced that it would recommend the nomination period open on April 3, 2023, and close on May 12, with the by-election to be held on June 26. The office of mayor was formally declared vacant during the March 29 city council meeting and a by-law was passed to confirm the by-election.

The number of candidates led to suggestion that the barrier to entry be increased.

Mayoral debates
Over 10 mayoral debates took place during the campaign. A planned debate at OCAD University (in collaboration with 60 Toronto residents' associations) scheduled to take place on June 1, 2023, was cancelled after threats were made to candidates prior to the event. A planned debate on climate action at the University of Toronto School of the Environment scheduled to take place on June 5, 2023, was cancelled due to scheduling conflicts.

Candidates
Registration for candidates for the office of mayor officially opened on April 3, 2023. The deadline for candidate nominations closed Friday, May 12 at 2 p.m. 105 candidates were nominated, with three candidates withdrawing their candidacy prior to the election. 102 candidates therefore ran for the office of mayor.

Declined

 * Stan Cho, provincial associate minister of transportation (2021–present) and Progressive Conservative MPP for Willowdale (2018–present).
 * Michael Clemons, general manager of the Toronto Argonauts and Canadian Football Hall of Famer.
 * Josh Colle, former city councillor for Eglinton—Lawrence (2010–2018) and former chair of the Toronto Transit Commission (2014–2018).
 * Joe Cressy, senior vice president at George Brown College, former city councillor for Spadina—Fort York (2014–2022).
 * Nathaniel Erskine-Smith, Liberal MP for Beaches—East York (2015–present).
 * Doug Ford, 26th premier of Ontario and Progressive Conservative MPP for Etobicoke North (2018–present), runner-up in the 2014 mayoral election, former city councillor for Etobicoke North (2010–2014).
 * Stephen Holyday, city councillor for Etobicoke Centre (2014–present).
 * Ahmed Hussen, federal minister of housing and diversity and inclusion (2021–present) and Liberal MP for York South—Weston (2015–present).
 * Bhutila Karpoche, New Democratic MPP for Parkdale—High Park (2018–present).
 * Jennifer Keesmaat, former chief city planner (2012–2017) and runner-up in the 2018 mayoral election.
 * Mike Layton, former city councillor for Ward 11 University—Rosedale (2018–2022) and Ward 19 Trinity—Spadina (2010–2018).
 * Marco Mendicino, federal minister of public safety (2021–present) and Liberal MP for Eglinton—Lawrence (2015–present).
 * Jennifer McKelvie, deputy mayor of Toronto (2022–present) and city councillor for Scarborough—Rouge Park (2018–present).
 * Denzil Minnan-Wong, former deputy mayor of Toronto (2014–2022) and former city councillor for Don Valley East (1998–2022).
 * Gil Peñalosa, runner-up in the 2022 mayoral election and urbanist.
 * Rod Phillips, former provincial minister of long-term care (2021–2022), minister of finance (2019–2020), minister of the environment, conservation and parks (2018–2019), Progressive Conservative MPP for Ajax (2018–2022).
 * Kristyn Wong-Tam, New Democratic MPP for Toronto Centre (2022–present) and former city councillor for Toronto Centre-Rosedale (2010–2022).
 * Kathleen Wynne, 25th premier of Ontario (2013–2018), former Liberal MPP for Don Valley West (2003–2022).

Opinion polls
Prior to campaign period
 * Campaign period

Results
The election took place on Monday, 26 June 2023, with official results certified by the City Clerk two days later. The turnout was 38.5%, around 9% higher than the 2022 election.