List of prime ministers of Canada by time in office

This is a list of Prime Ministers of Canada in order of time served in office as Prime Minister of Canada as of April 10, 2006. This list counts time during an election campaign as belonging to the preceding prime minister. See also List of Canadian political parties by time in office.

Rank	Prime Minister	incumbency	calendar incumbency	terms	breakdown
1	William Lyon Mackenzie King	7,766 days	21 years, 3 months, 6 days	6	in three blocks: 1,643 days + 1,351 days + 4,772 days
2	Sir John A. Macdonald*	6,934 days	18 years, 11 months, 24 days	6	in two blocks: 2, 319 days + 4,615 days
3	Pierre Trudeau	5,642 days	15 years, 5 months, 12 days	4	in two blocks: 4,062 days + 1,580 days
4	Sir Wilfrid Laurier	5,568 days	15 years, 2 months, 29 days	4
5	Jean Chrétien	3,690 days	10 years, 1 month, 8 days	3
6	Brian Mulroney	3,204 days	8 years, 9 months, 9 days	2
7	Sir Robert Borden	3,196 days	8 years, 9 months, 0 days	2
8	Louis St. Laurent	3,140 days	8 years, 7 months, 6 days	2
9	John Diefenbaker	2,131 days	5 years, 10 months, 1 day	3
10	Richard Bennett	1,903 days	5 years, 2 months, 16 days	1
11	Lester B. Pearson	1,825 days	4 years, 11 months, 29 days	2
12	Alexander Mackenzie	1,796 days	4 years, 11 months, 1 day	1
13	Paul Martin	787 days	2 years, 1 month, 25 days	1
14	Sir John Thompson	737 days	2 years, 0 months, 7 days	-
15	Arthur Meighen	686 days	1 year, 10 months, 15 days	-	in two blocks: 537 days + 149 days
16	Sir John Abbott	514 days	1 year, 4 months, 26 days	-
17	Sir Mackenzie Bowell	493 days	1 year, 4 months, 6 days	-
18	Joe Clark	273 days	8 months, 28 days	1
19	Kim Campbell	131 days	4 months, 9 days	-
20	John Turner	79 days	2 months, 18 days	-
21	Sir Charles Tupper	68 days	2 months, 7 days	-
22	Stephen Harper (incumbent)	63 days	2 months, 4 days	1

* Sir John A. Macdonald was also Joint Premier of the Province of Canada for 3,313 days (9 years, 27 days), giving him a total of 10,247 days (28 years, 20 days).