List of Prime Ministers of Canada by time in office

Prime ministers of Canada do not have a fixed term of office; instead, they may stay in office as long as their government is supported by parliament under a system of responsible government. Both the number of terms served and the length of individual terms have varied considerably since Confederation. Historically, elections have been held every three to five years, although since 2006 a government act set fixed election days every four years unless parliament is dissolved earlier by the Governor General. Prime ministers can be re-elected to serve any number of consecutive mandates, and some have served up to six terms, while several others have served for less than one full term. There are also four prime ministers who served multiple non-consecutive terms in the office.

Of the prime ministers who served less than one full term, two of them, Joe Clark and Paul Martin, had their time in office cut short by the collapse of a minority parliament and the subsequent election of the opposition party. In all other cases of short tenure, a new prime minister was put in place for the last few months of their predecessor's mandate—usually to try to gain support from the electorate before an election—but were subsequently defeated by the opposition party. The preceding Prime Minister always stays in office during an election campaign, and that time is included in the total. The first day of a Prime Minister's term is counted in the total, but the last day is not. This list is accurate as of January 30, 2017.

  Liberal Party of Canada   Conservative Party of Canada   Historical conservative parties/Progressive Conservative Party of Canada

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