| Dates: | 20 October 1940– 14 December 1940 |
| Number Edition: | 12th |
| Venue: | Clerical Union Hall |
| Location: | Balestier, Singapore |
| Ms: | Tan Chong Tee |
| Country Ms: | Straits Settlements |
| Ws: | Y. Yasuda |
| Country Ws: | JPN |
| Md1: | Chia Chin Soon |
| Country Md1: | Straits Settlements |
| Md2: | Ahmad Mattar |
| Country Md2: | Straits Settlements |
| Xd1: | Tan Chong Tee |
| Country Xd1: | Straits Settlements |
| Xd2: | Lee Shao Meng |
| Country Xd2: | Straits Settlements |
| Previous: | 1939 |
| Next: | 1941 |
The 1940 Singapore Open, also known as the 1940 Singapore Badminton Championships, took place from 20 October – 14 December 1940 at the Clerical Union Hall in Balestier, Singapore. The ties were played over a few months with the first round ties being played on the 20 of October[1] [2] and the last (men's doubles final) been played on 14 December.[3] [4] [5] There was no women's doubles competition due to the lack of entries.
| Category | Winners | Runners-up | Score | |
|---|---|---|---|---|
| Men's singles | Tan Chong Tee | Yap Chin Tee | 15–8, 15–6 | |
| Women's singles |  Y. Yasuda | Lee Shao Meng | 12–9, 9–12, 11–1 | |
| Men's doubles | Chia Chin Soon & Ahmad Mattar | 18–21, 21–16, 24–22 | ||
| Mixed doubles | Tan Chong Tee & Lee Shao Meng | S. A. Durai & Yoong Sook Lian | 15–21, 21–6, 21–3 |