| Gunnar Aaby | |
| Fullname: | Gunnar Nielsen Aaby |
| Birth Date: | 9 July 1895 |
| Birth Place: | Frederiksberg, Hovedstaden, Denmark |
| Death Place: | Gribskov, Hovedstaden, Denmark |
| Position: | Forward |
| Youthyears1: | –1912 |
| Youthclubs1: | Akademisk Boldklub u19 |
| Years1: | 1912–1929 |
| Clubs1: | Akademisk Boldklub |
Gunnar Nielsen Aaby (9 July 1895 in Frederiksberg, Hovedstaden, Denmark - 22 August 1966 in Gribskov, Hovedstaden, Denmark)[1] was a Danish soccer player in the 1920s.
At the 1920 Men's Olympic Football Tournament, his team lost to the Spanish team.[2] [3]