| Country: | Queensland |
| Type: | parliamentary |
| Ongoing: | no |
| Election Date: | 20 May 1939 |
| Vote Type: | Popular |
| Image1: | William Conelan.png |
| Candidate1: | William Conelan |
| Party1: | Australian Labor Party |
| Popular Vote1: | 22,967 |
| Percentage1: | 41.3% |
| Swing1: | 7.0pp |
| Candidate2: | Peter McCowan |
| Party2: | United Australia Party |
| Popular Vote2: | 17,168 |
| Percentage2: | 30.9 |
| Swing2: | 10.3pp |
| MP | |
| Before Election: | Frank Baker |
| Before Party: | Australian Labor Party |
| After Election: | William Conelan |
| After Party: | Australian Labor Party |
| Election Name: | 1939 Griffith by-election |
| 1Data2: | 50.0% |
| 2Blank: | TPP swing |
| 2Data1: | 0.3pp |
| 2Data2: | 0.3pp |
| 1Data1: | 50.0% |
| 1Blank: | TPP |
| Candidate3: | Everett Graham |
| Party3: | Protestant Labour |
| Popular Vote3: | 15,437 |
| Percentage3: | 27.8% |
| Swing3: | 27.8pp |
| Colour3: | CE7F30 |
A by-election was held for the Australian House of Representatives seat of Griffith on 20 May 1939. This was triggered by the death of Labor Party MP Frank Baker.
The election was won by Labor candidate William Conelan by eight votes.
Immediately after Baker's death, there was some speculation that Queensland premier, William Forgan Smith would contest the by-election.[1]