| Election Name: | 1966 Dawson by-election |
| Country: | Australia |
| Type: | Parliamentary |
| Ongoing: | no |
| Previous Election: | 1963 Australian federal election |
| Previous Year: | 1963 |
| Election Date: | 26 February 1966 |
| Next Election: | 1966 Australian federal election |
| Next Year: | 1966 |
| Turnout: | 37,377 (91.0%) |
| Seats For Election: | The Dawson seat in the House of Representatives |
| Candidate1: | Rex Patterson |
| Party1: | Australian Labor Party |
| Popular Vote1: | 20,372 |
| Percentage1: | 55.1% |
| Swing1: | 13.7 |
| Candidate2: | John Fordyce |
| Party2: | Australian Country Party (1920) |
| Popular Vote2: | 16,572 |
| Percentage2: | 44.9% |
| Swing2: | 6.9 |
| MP | |
| Before Election: | George Shaw |
| Before Party: | Australian Country Party (1920) |
| After Election: | Rex Patterson |
| After Party: | Australian Labor Party |
A by-election was held for the Australian House of Representatives seat of Dawson on 26 February 1966. This was triggered by the death of Country Party MP George Shaw.
The by-election was won by Labor candidate Rex Patterson.