| Léoncé Eugene Ernest Oleffe | |
| Nationality: | Belgian |
| Sport: | Middle-distance running |
| Event: | 800 metres |
| Birth Date: | 25 August 1897 |
| Birth Place: | Mont-Saint-Guibert, Belgium |
| Death Place: | Woluwé-Saint-Pierre, Belgium |
Léoncé Oleffe (25 August 1897 - 19 November 1972) was a Belgian middle-distance runner. He competed in the men's 800 metres at the 1920 Summer Olympics.[1]