New Democratic Party leadership elections, more commonly known as leadership conventions, are the process by which the Canadian New Democratic Party elects its leader.
Before 2003, when a modified one member, one vote (OMOV) system was adopted, every biennial New Democratic Party convention, since 1961, was a leadership convention. However, in practice, contested elections were held only when there was a declared leadership race. The earliest example of an incumbent leader being challenged from the convention floor happened in 1973 when Douglas Campbell unsuccessfully opposed David Lewis' leadership. In 2001, NDP Socialist Caucus member Marcel Hatch challenged Alexa McDonough from the floor of the convention; however, McDonough easily retained the leadership in the resulting vote.
When the NDP was created by the merger of the Co-operative Commonwealth Federation (CCF) and the Canadian Labour Congress (CLC), trade unions were allowed to directly affiliate to the party, and a system was unofficially arranged so that up to one-third of all delegates to NDP conventions were selected by labour and the other two-thirds by NDP riding associations. This was also the case at leadership conventions, giving the labour movement a significant say in determining the party's leadership. Under the current system, each biennial federal convention includes a vote at which the delegates decide whether a leadership convention should be held.
In practice, all three CCF leaders had been chosen by their parliamentary caucus and then elected unanimously at a subsequent national convention.
1961 leadership convention results
Held in Ottawa, Ontario on August 3, 1961.
{| class="wikitable"
|+ First Ballot
|-
! colspan="2" | Candidate
! Delegate Support
! Percentage
|- style="background:lightgreen;"
| 50px
| Tommy Douglas
| 1,391
| 78.5%
|-
| 50px
| Hazen Argue
| 380
| 21.5%
|-
! colspan="2" | Total
! 1,771
! 100%
|}
1971 leadership convention results
Held in Ottawa, Ontario on April 24, 1971.
{| class="wikitable"
|+ Delegate Support by Ballot
|-
! rowspan="2" colspan="2" | Candidate
! colspan="2" | 1st ballot
! colspan="2" | 2nd ballot
! colspan="2" | 3rd ballot
! colspan="2" | 4th ballot
|-
! Votes cast
! %
! Votes cast
! %
! Votes cast
! %
! Votes cast
! %
|- style="background:lightgreen;"
| 50px
| David Lewis
| 661
| 38.9%
| 715
| 42.5%
| 742
| 44.1%
| 1,046
| 63.1%
|-
|
| James Laxer
| 378
| 22.3%
| 407
| 24.1%
| 508
| 30.2%
| 612
| 36.9%
|-
| 50px
| John Paul Harney
| 299
| 17.6%
| 347
| 20.5%
| 431
| 25.6%
| style="text-align:center; background:pink;" colspan="2" | Eliminated
|-
| 50px
| Ed Broadbent
| 236
| 13.9%
| 223
| 13.1%
| style="text-align:center; background:pink;" colspan="4" | Eliminated
|-
| 50px
| Frank Howard
| 124
| 7.3%
| style="text-align:center; background:pink;" colspan="6" | Eliminated
|-
! colspan="2" | Total
! 1,698
! 100.0%
! 1,692
! 100.0%
! 1,681
! 100.0%
! 1,658
! 100.0%
|}
1973 leadership challenge results
Held in Vancouver, British Columbia on Friday, July 20, 1973.
{| class="wikitable"
|+ First Ballot
|-
! colspan="2" | Candidate
! Delegate Support
! Percentage
|- style="background:lightgreen;"
| 50px
| Alexa McDonough
| 645
| 84.31%
|-
|
|Marcel Hatch
| 120
| 15.69%
|-
! colspan="2" | Total
! 765
! 100%
|}
There were 42 spoiled ballots. If these are factored in McDonough's level of support was 78% overall.
2003 leadership election results
Held in Toronto, Ontario on January 25, 2003.
{| class="wikitable"
|+ First Ballot
|-
! colspan="2" | Candidate
! Votes<br />(Adjusted)
! Percentage
|- style="background:lightgreen;"
| 50px
| Jack Layton
| 31,150
| 53.5%
|-
| 50px
| Bill Blaikie
| 14,365
| 24.7%
|-
| 50px
| Lorne Nystrom
| 5,397
| 9.3%
|-
| 50px
| Joe Comartin
| 4,490
| 7.7%
|-
| 50px
| Pierre Ducasse
| 2,155
| 3.7%
|-
|
| Bev Meslo
| 645
| 1.1%
|-
! colspan="2" | Total
! 58,202
! 100%
|}
For this election, the NDP instituted a modified one member one vote system. Votes by labour delegates accounted for 25% of the total result, while votes cast by party members accounted for 75%. The carve out for labour was eliminated prior to the 2012 election.
2012 leadership election
The leadership convention was held at the Metro Toronto Convention Centre on March 24, 2012. There were 128,351 eligible voters, most voting from home and not delegates at the convention.
The party chose Thomas Mulcair as their new leader following the death of Jack Layton on August 22, 2011. A One member, one vote process was used.
: = Eliminated from next round
: = Withdrew nomination
: = Winner
{| class="wikitable"
|+ Support by Ballot
|-
! rowspan="2" colspan="2" | Candidate
! colspan="2" | 1st ballot
! colspan="2" | 2nd ballot
! colspan="2" | 3rd ballot
! colspan="2" | 4th ballot
|-
! Votes cast
! %
! Votes cast
! %
! Votes cast
! %
! Votes cast
! %
|- style="background:lightgreen;"
| 50px
| Tom Mulcair
| 19,728
| 30.3%
| 23,902
| 38.3%
| 27,488
| 43.8%
| 33,881
| 57.2%
|-
| 50px
| Brian Topp
| 13,915
| 21.4%
| 15,624
| 25.0%
| 19,822
| 31.6%
| 25,329
| 42.8%
|-
| 50px
| Nathan Cullen
| 10,671
| 16.4%
| 12,449
| 19.9%
| 15,426
| 24.6%
| style="text-align:center; background:pink;" colspan="2" | Did not endorse
|-
| 50px
| Peggy Nash
| 8,353
| 12.8%
| 10,519
| 16.8%
| style="text-align:center; background:pink;" colspan="4" | Did not endorse
|-
| 50px
| Paul Dewar
| 4,883
| 7.5%
| style="text-align:center; background:pink;" colspan="6" | Did not endorse
|-
| 50px
| Martin Singh
| 3,821
| 5.9%
| style="text-align:center; background:lightblue;" colspan="6" | Endorsed Mulcair
|-
| 50px
| Niki Ashton
| 3,737
| 5.7%
| style="text-align:center; background:pink;" colspan="6" | Did not endorse
|-
| 50px
| Roméo Saganash
| style="text-align:center; background:lightblue;" colspan="8" | Endorsed Mulcair
|-
| 50px
| Robert Chisholm
| style="text-align:center; background:lightblue;" colspan="8" | Endorsed Mulcair
|-
! colspan="2" | Total
! 65,108
! 100.0%
! 62,494
! 100.0%
! 62,736
! 100.0%
! 59,210
! 100.0%
|}
2017 leadership election
Voting was held between September 18 to October 1, 2017. The results were announced on October 1 in Toronto, Ontario at the Westin Harbour Castle.
{|class="wikitable"
|+ First Ballot
|-
! colspan="2"| Candidate
! Votes
! Percentage
|- style="background:lightgreen;"
|50px|| Jagmeet Singh || style='text-align:center'| 35,266 ||style='text-align:center'| 53.8%
|-
|50px|| Charlie Angus|| style="text-align:center" | 12,705 ||style='text-align:center'| 19.4%
|-
||50px|| Niki Ashton|| style="text-align:center" | 11,374 ||style='text-align:center'| 17.4%
|-
||50px|| Guy Caron|| style="text-align:center" | 6,164 ||style='text-align:center'| 9.4%
|-
! colspan = "2" style="text-align:left;"|Total ||style='text-align:center'| 65,782 ||style='text-align:center'|100%
|}
- Spoiled ballots: 101
- Abstentions: 172
- Turnout: 52.8% (1.9pp)
2026 leadership election
Voting was held between March 9 and 28, 2026. The results were announced on March 29 in Winnipeg, Manitoba, at the RBC Convention Centre.