| Strokes: | Backstroke |
| Club: | Stockholms KK |
| Birth Date: | 15 April 1893 |
| Birth Place: | Stockholm, Sweden |
| Death Date: | 20 July 1946 (aged 53) |
| Death Place: | Redding, California, United States |
| Show-Medals: | yes |
Gunnar Isidor Sundman (15 April 1893 – 20 July 1946) was a Swedish swimmer.[1] He competed at the 1912 Summer Olympics in the 100 m backstroke event, but failed to reach the final.
Sundman later immigrated to the United States where he continued to swim and worked as an engineer with the California Department of Transportation. He served in World War I.