| 1940 Australian Championships | |
|---|---|
| Date | 19–29 January 1940 |
| Edition | 33rd |
| Category | Grand Slam (ITF) |
| Surface | Grass |
| Location | Sydney, Australia |
| Venue | White City Tennis Club |
| Champions | |
| Men's singles | |
 Adrian Quist | |
| Women's singles | |
| Nancye Wynne | |
| Men's doubles | |
| John Bromwich / Adrian Quist | |
| Women's doubles | |
| Thelma Coyne / Nancye Wynne | |
| Mixed doubles | |
| Nancye Wynne / Colin Long | |
| Boys' singles | |
| Dinny Pails | |
| Girls' singles | |
| Joyce Wood | |
| Boys' doubles | |
| William Edwards / Dinny Pails | |
| Girls' doubles | |
| Alison Burton / Joyce Wood | |
The 1940 Australian Championships was a tennis tournament that took place on outdoor Grass courts at the White City Tennis Club, Sydney, Australia from 19 January to 29 January. It was the 33rd edition of the Australian Championships (now known as the Australian Open), the 9th held in Sydney, and the first Grand Slam tournament of the year. The singles titles were won by Australians Adrian Quist and Nancye Wynne.