| Courtoin | |
| Commune Status: | Commune |
| Coordinates: | 48.1244°N 3.1089°W |
| Insee: | 89126 |
| Postal Code: | 89150 |
| Arrondissement: | Sens |
| Canton: | Gâtinais en Bourgogne |
| Mayor: | Christine Aita[1] |
| Term: | 2020 - 2026 |
| Elevation Min M: | 164 |
| Elevation Max M: | 190 |
| Area Km2: | 6.15 |
Courtoin (in French pronounced as /kuʁtwɛ̃/) is a commune in the Yonne department in Bourgogne-Franche-Comté in north-central France.
The commune is traversed by the Lunain river.