| Leo Nielsen | |
| Fullname: | Carl Leo Holger Nielsen |
| Birth Date: | 5 March 1909 |
| Birth Place: | Randers, Denmark |
| Death Place: | Copenhagen, Denmark |
| Show-Medals: | yes |
Carl Leo Holger Nielsen (5 March 1909 - 15 June 1968) was a Danish track cyclist who won a gold medal at the 1928 Summer Olympics with Henry Hansen and Orla Jørgensen and a silver medal at the 1932 Summer Olympics with Hansen and Frode Sørensen.[1]