| Country: | New South Wales |
| Type: | parliamentary |
| Ongoing: | no |
| Election Date: | 31 January 1931 |
| Vote Type: | Popular |
| Image1: | Sir Charles Marr (cropped).jpg |
| Candidate1: | Charles Marr |
| Party1: | Nationalist Party (Australia) |
| Popular Vote1: | 31,227 |
| Percentage1: | 56.8% |
| Swing1: | 14.6pp |
| Candidate2: | Joseph Martin |
| Party2: | Australian Labor Party |
| Popular Vote2: | 22,394 |
| Percentage2: | 40.7% |
| Swing2: | 17.1pp |
| MP | |
| Before Election: | Edward McTiernan |
| Before Party: | Australian Labor Party |
| After Election: | Charles Marr |
| After Party: | Nationalist Party (Australia) |
| Election Name: | 1931 Parkes by-election |
| 1Data2: | 42.2% |
| 2Blank: | TPP swing |
| 2Data1: | 15.6pp |
| 2Data2: | 42.2pp |
| 1Data1: | 57.8% |
| 1Blank: | TPP |
A by-election was held for the Australian House of Representatives seat of Parkes on 31 January 1931. This was triggered by the resignation of Labor MP Edward McTiernan to take a seat on the High Court.
The by-election was won by Nationalist candidate Charles Marr, who had represented the seat from 1919 until his defeat by McTiernan in 1929.
This was the first time the Communist Party endorsed a candidate at federal level.