| Saint-Martin-sur-Ouanne | |
| Coordinates: | 47.8408°N 3.1053°W |
| Insee: | 89358 |
| Postal Code: | 89120 |
| Arrondissement: | Auxerre |
| Canton: | Charny Orée de Puisaye |
| Commune: | Charny-Orée-de-Puisaye |
| Elevation Min M: | 136 |
| Elevation Max M: | 202 |
| Area Km2: | 15.34 |
| Population: | 381 |
| Population Date: | 2019 |
| Population Footnotes: | [1] |
Saint-Martin-sur-Ouanne is a former commune in the Yonne department in Bourgogne-Franche-Comté in north-central France. On 1 January 2016, it was merged into the new commune of Charny-Orée-de-Puisaye.[2]
The village lies on the right bank of the Ouanne, which flows northward through the commune.