| Election Name: | 1940 Waipawa by-election |
| Country: | New Zealand |
| Flag Year: | 1940 |
| Type: | presidential |
| Previous Election: | 1938 New Zealand general election |
| Previous Year: | 1938 general |
| Next Election: | 1943 New Zealand general election |
| Next Year: | 1943 general |
| Turnout: | 8,136 (76.14%) |
| Candidate1: | Cyril Harker |
| Party1: | New Zealand National Party |
| Popular Vote1: | 4,913 |
| Percentage1: | 60.64 |
| Candidate2: | Max Christie |
| Party2: | New Zealand Labour Party |
| Popular Vote2: | 3,189 |
| Percentage2: | 39.36 |
| MP | |
| Before Election: | Albert Jull |
| Before Party: | New Zealand National Party |
| After Party: | New Zealand National Party |
The Waipawa by-election of 1940 was a by-election for the electorate of Waipawa held on 16 November 1940 during the 26th New Zealand Parliament. The by-election resulted from the death of the previous member Albert Jull on 24 September 1940.
The by-election was won by Cyril Harker, also of the National Party. The rural seat was usually safe for non-Labour parties, but in the 1935 general election had been won by Max Christie of the Labour Party. Christie lost the seat to the former holder Albert Jull in the 1938 general election.
The following table gives the election results: