Municipal elections were held on October 22, 2018, to elect a mayor and city councillors in Toronto, Ontario, Canada. Registration for candidates for the office of mayor, councillor, and school board trustee opened on May 1, 2018, and initially closed on July 27, 2018. John Tory won the mayoral election with over 60% of the vote.

To account for the city's growing population, Toronto's council wards underwent a realignment. With the removal of a ward in the west end, three new wards added in the downtown area, and a new ward in North York, this expanding the city from 44 wards to 47 wards. In July 2018, newly-elected Premier of Ontario Doug Ford introduced legislation to require that Toronto's municipal elections use the same ridings as it does for provincial and federal elections, thus reducing the council to 25 wards. The bill attracted controversy for its intent to change electoral boundaries in the middle of a campaign, and was struck down as unconstitutional in September 2018 but a stay on this ruling was granted nine days later by the Court of Appeal for Ontario. The three judge panel ruled the bill was constitutional and that the previous ruling was "dubious", thus reinstating the 25-ward election.

Seventeen Toronto councillors were elected with less than half of all votes cast. One councillor, Cynthia Lai was elected with approximately 27% of the votes cast.

Ward boundary adjustment The Toronto City Council commissioned an independent review of its ward boundaries in order to account for predicted population growth in specific areas of the city. The consultants recommended the realignment of the city's 44 wards into 47. Under the 47-ward model, wards would not achieve voter parity until 2026 (when the population projection of 61,000 residents per ward would eventually kick in). The Supreme Court considers voter parity to be crucial to achieving effective representation.

Three new wards were added in downtown, one in North York, while one was removed from Toronto's west end by consolidating 3 wards into 2. Based on the patterns of incumbents shifting to successor wards, the four "new" wards are Ward 20, Ward 21, Ward 25 and Ward 29; the ward reduction in the west end is reflected in the effective merger of what had been designated as Ward 17 and Ward 18 on the preceding map into new Ward 16.

Two city councillors, Giorgio Mammoliti and Justin Di Ciano, along with several Toronto citizens, appealed the redrawing of ward boundaries at the Ontario Municipal Board. The appeal was rejected and new ward boundaries approved in a 38-page decision. The council had to pass a by-law before January 2018 for the boundaries to be changed before the election.

Reduction of wards On July 27, 2018, the last day for candidate registration, former councillor and new Ontario Premier Doug Ford introduced the Better Local Government Act, also known as Bill 5. The legislation requires that the Toronto city council align its municipal wards with those of the federal and provincial electoral ridings, thus reducing the size of Toronto's council from 47 to 25 wards. Each council member would serve an area representing an average of 111,000 residents. Ford justified the legislation by stating that the council had "failed to act on the critical issues facing the city", and that expanding it to 47 wards would exacerbate the existing "dysfunction". The province claimed that such a reduction would result in a savings of $25 million over the next four years (in comparison to the city's operating budget of $11.12 billion per-year). The bill also cancelled pending elections for regional chair in the regional municipalities of Niagara and Muskoka, Peel, and York, resetting all four positions back to appointed, rather than elected, offices.

The bill proved controversial, with the official opposition Ontario NDP disputing its intent and considering it an abuse of power, while other groups (including candidates and the Toronto District School Board) contended that the bill undermined the democratic process. Toronto mayor John Tory suggested that such significant changes be subject to a public referendum. Toronto's city council voted 24-17 on a motion to oppose Bill 5 and support Tory's call for a referendum. Tory also criticized Ford for not providing any opportunities to consult with the municipal government over the bill. Ford denied Tory's statement, stating that he had met with Tory and other officials multiple times. Bill 5 was passed August 14, 2018. Rocco Achampong, a candidate for one of the wards removed in the consolidation, launched a legal challenge over the bill in the Ontario Superior Court.

The government of Ontario argued that the larger wards were intended to improve voter parity for the 2018 municipal election (as the 47 ward model would not achieve voter parity until 2026). However, the city asserted that the 25-ward model provided no better parity than the newly-implemented 47-ward structure, and a consultant argued that the roughly doubled ward population reduced councillors' capacity to serve their communities—another aspect of effective representation. In an affidavit, Toronto city manager Giuliana Carbone disputed the claimed cost savings, stating that it would only save $6 million over four years, taking into account the increased staffing that would be required to operate the larger wards, and the costs incurred by realigning the election to match the new boundaries.

On September 10, 2018, the Better Local Government Act was struck down as unconstitutional by Superior Court Justice Edward Belobaba, ruling that the larger wards infringed on citizens' rights to effective electoral representation, and that unilaterally changing electoral boundaries in the middle of a campaign infringed on candidates' freedom of expression. He explained that "passing a law that changes the city's electoral districts in the middle of its election and undermines the overall fairness of the election is antithetical to the core principles of our democracy", and questioned the province's intent and timing of the legislation. Ford criticized the ruling, contending that its only supporters were a "small group of left-wing councillors looking to continue their free ride on the taxpayers' dollar and a network of activist groups who have entrenched their power under the status quo."

The Ford government introduced the Efficient Local Government Act, also known as Bill 31, on September 12, 2018. The bill would have invoked Section 33 of the Canadian Charter of Rights and Freedoms, also known as the notwithstanding clause, to implement the effects of Bill 5 in defiance of the court ruling. If passed, it would have been the first time that the notwithstanding clause had ever been invoked in Ontario. The Toronto city council voted 29–7 in favour of directing the city solicitor to challenge the new legislation in court, and to ask the federal government to invoke a constitutional clause allowing it to disallow provincial legislation (a mechanism only used once since 1943) should it pass. At a Liberal Party caucus retreat in Saskatoon, Prime Minister Justin Trudeau stated that he would not contribute to the discussions surrounding the sizes of municipal governments in Ontario, as it was "[not] a role that the federal government needs to take on".

On September 19, 2018, the Court of Appeal for Ontario in Toronto (City) v Ontario (Attorney General) issued a stay on the previous Superior Court decision, ruling that Bill 5 "disrupted the campaigns that were already underway" but "does not limit or restrict any message the candidates wish to convey to voters", and was a "dubious ruling that invalidates legislation duly passed by the legislature". As such, the election would be required to use the 25-ward alignment mandated by Bill 5. Since it was made redundant by the stay, Bill 31 was also withdrawn. The nomination period was reopened as a result of the stay and closed on September 21, 2018.

In a judgment rendered October 1, 2021, the Supreme Court of Canada upheld the constitutionality of the provisions, and the 25-ward model remained in effect for this and the following 2022 Toronto municipal election.

City Council (25-ward model)

Ward 1 Etobicoke North Candidate Votes Percentage Registration Date Notes(incumbent)Michael Ford10,64842.26%July 4, 2018Councillor for former Ward 2 since 2016. Nephew of Ontario Premier Doug Ford. Endorsed by Toronto Sun.(incumbent)Vincent Crisanti8,65434.34%May 1, 2018Councillor for former Ward 1 since 2010.Naiima Farah2,2628.98%July 27, 2018Shirish Patel1,9457.72%May 1, 2018Carol Royer6422.55%July 27, 2018Endorsed by Toronto Star and NOW magazine.Michelle Garcia4391.74%July 26, 2018Peter D'Gama2531.00%July 20, 2018Christopher Noor2140.85%July 9, 2018Gurinder Patri1420.56%July 27, 2018

Ward 2 Etobicoke Centre Candidate Votes Percentage Registration Date Notes(incumbent)Stephen Holyday14,62738.58%June 4, 2018Councillor for former Ward 3 since 2014. Endorsed by Toronto Sun.(incumbent)John Campbell13,44135.45%May 4, 2018Councillor for former Ward 4 since 2014. Endorsed by Toronto Star.Angelo Carnevale5,73515.13%June 13, 2018Erica Kelly3,85410.16%July 16, 2018NDP candidate in 2018 provincial election. Endorsed by NOW magazine.Bill Boersma2580.68%July 27, 2018

Ward 3 Etobicoke—Lakeshore Candidate Votes Percentage Registration Date Notes(incumbent)Mark Grimes16,52740.90%July 25, 2018Councillor for former Ward 6 since 2003. Endorsed by Toronto Sun.Amber Morley10,98527.19%May 10, 2018Endorsed by Toronto & York District Labour Council, Progress Toronto, Toronto Star, and NOW magazine.Pamela Gough7,30118.07%May 1, 2018TDSB school trusteeIain Davis2,7226.74%July 27, 2018Svitlana Burlakova1,2183.01%July 27, 2018Peggy Moulder5751.42%July 27, 2018Patrizia Nigro3940.98%May 31, 2018Michael Julihen3200.79%August 29, 2018Michael Loomans1990.49%July 5, 2018Robert Gunnyon1670.41%September 20, 2018

Ward 4 Parkdale—High Park Candidate Votes Percentage Registration Date Notes(incumbent)Gord Perks16,88744.55%May 1, 2018Councillor for former Ward 14 since 2006. Endorsed by Toronto & York District Labour Council, the Toronto Star, Jennifer Keesmaat, and NOW magazine.David Ginsberg8,18121.58%July 16, 2018Kalsang Dolma5,35214.12%May 7, 2018Evan Tummillo2,3676.24%May 1, 2018Endorsed by Toronto Sun.Valerie Grdisa1,7714.67%September 21, 2018Nick Pavlov8742.31%July 27, 2018Taras Kulish8682.29%July 27, 2018Alex Perez6861.81%July 27, 2018José Vera5441.44%June 29, 2018Mercy Okalowe3730.98%July 12, 2018

Ward 5 York South—Weston Candidate Votes Percentage Registration Date Notes(incumbent)Frances Nunziata8,42532.18%June 4, 2018Councillor for former Ward 11 since 2000. Endorsed by Toronto Sun.(incumbent)Frank Di Giorgio5,67421.67%May 4, 2018Councillor for former Ward 12 since 2000Chiara Padovani5,35820.47%May 1, 2018Endorsed by Progress TorontoLekan Olawoye3,88914.85%May 1, 2018 Endorsed by Toronto & York District Labour Council, Toronto Star, and NOW magazine.Deega Barre1,1724.48%May 16, 2018Keaton Austin4671.78%July 26, 2018Luis Portillo3521.34%June 6, 2018Fred Fosu2450.94%July 27, 2018Joey Carapinha2410.92%May 1, 2018Cedric Ogalvie1890.72%July 24, 2018Harpeet Gulri1680.64%July 23, 2018

Ward 6 York Centre Candidate Votes Percentage Registration Date Notes(incumbent)James Pasternak11,559 47.61%May 15, 2018Councillor for former Ward 10 since 2010. Endorsed by Toronto Sun.(incumbent)Maria Augimeri9,22337.99%May 1, 2018Councillor for former Ward 9 since 2000. Endorsed by Toronto & York District Labour Council, Toronto Star, and NOW magazine.Louise Russo2,72611.23%July 20, 2018Sought Liberal nomination for the 2018 provincial election in York Centre Prominent anti-violence advocate, namesake of a city park in neighbouring Ward 7 Humber River—Black CreekEdward Zaretsky7713.17%July 23, 2018Operator of community group, Citizens Alliance Group. Ran for city council in 2010.