List of Ontario by-elections

The list of Ontario by-elections includes every by-election held in the Canadian province of Ontario. By-elections occur whenever there is a vacancy in the Legislative Assembly, although an imminent general election may allow the vacancy to remain until the dissolution of parliament.

Causes A by-election occurs whenever there is a vacancy in the Ontario legislature. Vacancies can occur for the following reasons:

Death of a member. Resignation of a member. Voided results Expulsion from the legislature. Ineligibility to sit.

When there is a vacancy, the writ for a by-election must be issued within six months. The writ is issued on a Wednesday, the election date must be a Thursday and must be 29 days after the writ is issued. Under amendments to the Election Act approved in 2016, a by-election is no longer required when a vacancy occurs in the 12 months leading up to a fixed general election date.

Ministerial by-elections The list includes ministerial by-elections which occurred due to the requirement that incumbent members recontest their seats upon being appointed to Cabinet. These by-elections were almost always uncontested. This requirement was amended in 1926 to exempt ministers appointed within three months after a general election. In 1941 it was abolished completely. 44th Legislative Assembly of Ontario 2025–present

By-election Date Incumbent Party Winner Party Cause RetainedHamilton East—Stoney CreekSeptember 3, 2026Neil Lumsden    Progressive ConservativeJeff Beattie    Progressive ConservativeRetiredYesYork—Simcoe September 3, 2026Caroline Mulroney    Progressive ConservativeSusan Lahey    Progressive ConservativeResigned to return to private life.YesScarborough SouthwestSeptember 3, 2026Doly Begum    New DemocraticFatima Shaban    New DemocraticResigned to run in a federal by-election.Yes

43rd Legislative Assembly of Ontario 2022–2025

By-election Date Incumbent Party Winner Party Cause RetainedBay of QuinteSeptember 19, 2024Todd Smith    Progressive ConservativeTyler Allsopp    Progressive ConservativeResigned to return to the private sector.YesMiltonMay 2, 2024Parm Gill    Progressive ConservativeZee Hamid    Progressive ConservativeResigned to run for a seat in the House of CommonsYesLambton—Kent—MiddlesexMay 2, 2024Monte McNaughton    Progressive ConservativeSteve Pinsonneault    Progressive ConservativeResigned to return to the private sectorYesKitchener CentreNovember 30, 2023Laura Mae Lindo   New DemocraticAislinn Clancy   GreenResigned to take up role at University of Waterloo.NoScarborough—GuildwoodJuly 27, 2023Mitzie Hunter   LiberalAndrea Hazell   LiberalResigned to run for Mayor of Toronto, lost.YesKanata—CarletonJuly 27, 2023Merrilee Fullerton    Progressive ConservativeKaren McCrimmon   LiberalResigned.NoHamilton CentreMarch 16, 2023Andrea Horwath   New DemocraticSarah Jama   New DemocraticResigned to run for Mayor of Hamilton, elected.Yes

42nd Legislative Assembly of Ontario 2018–2022

By-election Date Incumbent Party Winner Party Cause RetainedOttawa—VanierFebruary 27, 2020Nathalie Des Rosiers   LiberalLucille Collard    LiberalResigned to become Principal of Massey CollegeYesOrléansFebruary 27, 2020Marie-France Lalonde   LiberalStephen Blais    LiberalResigned to run in the federal district of Orléans; elected.Yes

41st Legislative Assembly of Ontario 2014–2018

By-election Date Incumbent Party Winner Party Cause RetainedSault Ste. MarieJune 1, 2017David Orazietti    LiberalRoss Romano    Progressive ConservativeResignation.NoNiagara West—GlanbrookNovember 17, 2016Tim Hudak    Progressive ConservativeSam Oosterhoff    Progressive ConservativeResignation to become CEO of Ontario Real Estate Association.YesOttawa—VanierNovember 17, 2016Madeleine Meilleur    LiberalNathalie Des Rosiers    LiberalResignation.YesScarborough—Rouge RiverSeptember 1, 2016Bas Balkissoon    LiberalRaymond Cho    Progressive ConservativeResignation.NoWhitby—OshawaFebruary 11, 2016Christine Elliott    Progressive ConservativeLorne Coe    Progressive ConservativeResigned after losing leadership contest.YesSimcoe NorthSeptember 3, 2015Garfield Dunlop    Progressive ConservativePatrick Brown    Progressive ConservativeResignation to create a vacancy for PC leader Brown.YesSudburyFebruary 5, 2015Joe Cimino    New DemocraticGlenn Thibeault     LiberalResignation.No

40th Legislative Assembly of Ontario 2011–2014

By-election Date Incumbent Party Winner Party Cause RetainedThornhillFebruary 13, 2014Peter Shurman   Progressive ConservativeGila Martow   Progressive ConservativeResignationYesNiagara FallsFebruary 13, 2014Kim Craitor   LiberalWayne Gates   New DemocraticResignationNoScarborough—GuildwoodAugust 1, 2013Margarett Best   LiberalMitzie Hunter   LiberalResignationYesEtobicoke—LakeshoreAugust 1, 2013Laurel Broten   LiberalDoug Holyday   Progressive ConservativeResignationNoOttawa SouthAugust 1, 2013Dalton McGuinty   LiberalJohn Fraser   LiberalResignation to re-enter private life after retiring as Premier and Liberal leader.YesWindsor—TecumsehAugust 1, 2013Dwight Duncan   LiberalPercy Hatfield   New DemocraticResignation following the retirement of Premier McGuintyNoLondon WestAugust 1, 2013Chris Bentley   LiberalPeggy Sattler   New DemocraticResignation following the retirement of Premier McGuintyNoKitchener—WaterlooSeptember 6, 2012Elizabeth Witmer   Progressive ConservativeCatherine Fife   New DemocraticResignation to accept appointment as Chair of the Workplace Safety & Insurance BoardNoVaughanSeptember 6, 2012Greg Sorbara   LiberalSteven Del Duca   LiberalResignation Yes

39th Legislative Assembly of Ontario 2007–2011

By-election Date Incumbent Party Winner Party Cause RetainedOttawa West—NepeanMarch 4, 2010Jim Watson    LiberalBob Chiarelli    LiberalResignation to run for Mayor of OttawaYesLeeds—GrenvilleMarch 4, 2010Robert Runciman   Progressive ConservativeSteve Clark   Progressive ConservativeResignation upon appointment to Canadian Senate.YesToronto CentreFebruary 4, 2010George Smitherman    LiberalGlen Murray    LiberalResignation to run for Mayor of Toronto.YesSt. Paul'sSeptember 17, 2009Michael Bryant    LiberalEric Hoskins    LiberalResignation to accept municipal appointment.YesHaliburton—Kawartha Lakes—BrockMarch 5, 2009Laurie Scott   Progressive ConservativeRick Johnson    LiberalResignation to create vacancy for PC leader John Tory.No

38th Legislative Assembly of Ontario 2003–2007

By-election Date Incumbent Party Winner Party Cause RetainedBurlingtonFebruary 8, 2007Cam Jackson   Progressive ConservativeJoyce Savoline   Progressive ConservativeResignation to run for Mayor of BurlingtonYesYork South—WestonFebruary 8, 2007Joe Cordiano    LiberalPaul Ferreira   New DemocraticResignationNoMarkhamFebruary 8, 2007Tony Wong    LiberalMichael Chan    LiberalResignation to run municipally.YesParkdale—High ParkSeptember 14, 2006Gerard Kennedy    LiberalCheri DiNovo   New DemocraticResignation to seek federal Liberal leadership.NoWhitby—AjaxMarch 30, 2006Jim Flaherty   Progressive ConservativeChristine Elliott   Progressive ConservativeResignation to run federally.YesToronto—DanforthMarch 26, 2006Marilyn Churley    New DemocraticPeter Tabuns    New DemocraticResignation to run federally.YesNepean—CarletonMarch 26, 2006John Baird   Progressive ConservativeLisa MacLeod   Progressive ConservativeResignation to run federally.YesScarborough—Rouge RiverNovember 24, 2005Alvin Curling    LiberalBas Balkissoon    LiberalResignation to accept diplomatic posting.YesDufferin—Peel—Wellington—GreyMarch 17, 2005Ernie Eves   Progressive ConservativeJohn Tory   Progressive ConservativeResignation.YesHamilton EastMay 13, 2004Dominic Agostino    LiberalAndrea Horwath   New DemocraticDeathNo

37th Legislative Assembly of Ontario 1999–2003

By-election Date Incumbent Party Winner Party Cause RetainedDufferin—Peel—Wellington—GreyMay 2, 2002David Tilson   Progressive ConservativeErnie Eves   Progressive ConservativeResignation to create vacancy for PC leader and Premier Ernie Eves.YesNipissingMay 2, 2002Mike Harris   Progressive ConservativeAl McDonald   Progressive ConservativeResignation after retiring as Premier and party leader.YesBeaches-East YorkSeptember 20, 2001Frances Lankin   New DemocraticMichael Prue   New DemocraticResignation to become CEO of United Way TorontoYesVaughan—King—AuroraJune 28, 2001Al Palladini   Progressive ConservativeGreg Sorbara    LiberalDeathNoParry Sound—MuskokaMarch 22, 2001Ernie Eves   Progressive ConservativeNorm Miller   Progressive ConservativeResignationYesWentworth-BurlingtonSeptember 7, 2000Toni Skarica   Progressive ConservativeTed McMeekin    LiberalResignation to protest municipal amalgamation.No

36th Legislative Assembly of Ontario 1995–1999

By-election Date Incumbent Party Winner Party Cause RetainedNickel BeltOctober 1, 1998Floyd Laughren   New DemocraticBlain Morin   New DemocraticResignation to accept appointment as chair of Ontario Energy BoardYesOrioleSeptember 4, 1997Elinor Caplan    LiberalDavid Caplan    LiberalResignation to enter federal politicsYesOttawa WestSeptember 4, 1997Bob Chiarelli    LiberalAlex Cullen    LiberalResignation to run municipallyYesWindsor—RiversideSeptember 4, 1997Dave Cooke   New DemocraticWayne Lessard   New DemocraticResignation to accept provincial appointment to the Education Improvement Commission.YesYork SouthMay 23, 1996Bob Rae   New DemocraticGerard Kennedy    LiberalResignation.No

35th Legislative Assembly of Ontario 1990–1995

By-election Date Incumbent Party Winner Party Cause RetainedVictoria—HaliburtonMarch 17, 1994Dennis Drainville   IndependentChris Hodgson   Progressive ConservativeResignation to run federally.NoEssex SouthDecember 2, 1993Remo Mancini    LiberalBruce Crozier    LiberalResignationYesSt. George—St. DavidApril 1, 1993Ian Scott    LiberalTim Murphy    LiberalResignationYesDon MillsApril 1, 1993Margery Ward   New DemocraticDavid Johnson   Progressive ConservativeDeathNoBrant—HaldimandMarch 5, 1992Robert Nixon    LiberalRonald Eddy    LiberalResignation to accept federal appointment.Yes

34th Legislative Assembly of Ontario 1987–1990

By-election Date Incumbent Party Winner Party Cause RetainedWelland—ThoroldNovember 3, 1988Mel Swart   New DemocraticPeter Kormos   New DemocraticResignation.YesLondon NorthMarch 31, 1988Ron Van Horne    LiberalDianne Cunningham   Progressive ConservativeResignation.No

33rd Legislative Assembly of Ontario 1985–1987

By-election Date Incumbent Party Winner Party Cause RetainedCochrane NorthAugust 14, 1986René Fontaine    LiberalRené Fontaine    LiberalResignation from cabinet and legislature to resubmit candidacy to voters after it was revealed he had forgotten to disclose his ownership of shares in a mining company contrary to conflict of interest guidelines.YesYork EastApril 17, 1986Robert Elgie   Progressive ConservativeChristine Hart    LiberalResignation to accept appointment as head of Workers Compensation Board.No

32nd Legislative Assembly of Ontario 1981–1985