List of federal by-elections in Canada

This is a list of by-elections in Canada since Confederation. By-elections are held to fill a vacancy in the Canadian House of Commons. Vacancies are caused by the death or resignation of a Member of Parliament or, more rarely, by the voiding of an election result by a court or as the result of an MP being expelled from the House of Commons. MPs have been expelled four times - Louis Riel (Provencher) was expelled in 1874 and again in 1875 for being a fugitive, Fred Rose (Cartier) was expelled in 1947 after having been convicted under the Official Secrets Act for having allegedly spied for the Soviet Union. In 1891, Thomas McGreevy (Quebec West) was expelled after being sentenced to a year in prison following his conviction for defrauding the government.

When a seat becomes vacant the Speaker of the House of Commons of Canada issues a "Speaker's warrant" informing the Chief Electoral Officer of Canada of a vacancy. The Chief Electoral Officer must issue a writ of election "between the 11th and 180th days after the Chief Electoral Officer receives the warrant from the Speaker". The election date is then set for not less than 36 days and not more than 50 days after the issuance of the writ. If a vacancy occurs less than nine months before a fixed election date, then no by-election is held and the seat remains vacant until the general election.

This list below includes ministerial by-elections which occurred due to the requirement that Members of Parliament recontest their seats upon being appointed to Cabinet. These by-elections were almost always uncontested. This requirement was abolished in 1931.