| Election Name: | 1918 Palmerston by-election |
| Country: | New Zealand |
| Flag Year: | 1918 |
| Type: | By-election |
| Ongoing: | no |
| Previous Election: | 1914 New Zealand general election |
| Previous Year: | 1914 general |
| Next Election: | 1919 New Zealand general election |
| Next Year: | 1919 general |
| Turnout: | 5,363 |
| Candidate1: | Jimmy Nash |
| Party1: | Reform Party (New Zealand) |
| Popular Vote1: | 2,229 |
| Percentage1: | 41.56 |
| Candidate2: | Alexander Galbraith |
| Party2: | New Zealand Labour Party |
| Popular Vote2: | 1,914 |
| Percentage2: | 35.68 |
| Candidate3: | Ernest Hugh Crabb |
| Party3: | New Zealand Liberal Party |
| Popular Vote3: | 1,119 |
| Percentage3: | 20.86 |
| Member | |
| Before Election: | David Buick |
| After Election: | Jimmy Nash |
| Before Party: | Reform Party (New Zealand) |
| After Party: | Reform Party (New Zealand) |
The Palmerston by-election of 1918 was a by-election held in the electorate during the 19th New Zealand Parliament, on 19 December 1918. The by-election was won by the sitting Mayor of Palmerston North, Jimmy Nash with a majority of 315.
The contest was triggered by the death of incumbent MP David Buick of the Reform Party on 18 November 1918 during the influenza epidemic.[1] Under the terms of the coalition agreement between Reform and the Liberal's a condition was made not to oppose each other in by-elections for deceased or retiring MP's from their own parties. However, both contested the seat after failing to agree on a joint National Government nominee.
The following table gives the election results: