| Filain | |
| Commune Status: | Commune |
| Arrondissement: | Soissons |
| Canton: | Fère-en-Tardenois |
| Insee: | 02311 |
| Postal Code: | 02000 |
| Mayor: | Hubert de Vriendt[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Val de l'Aisne |
| Coordinates: | 49.46°N 3.5564°W |
| Elevation M: | 178 |
| Elevation Min M: | 64 |
| Elevation Max M: | 198 |
| Area Km2: | 4.78 |
Filain (pronounced as /fr/) is a commune in the Aisne department in Hauts-de-France in northern France.
The river Ailette forms all of the commune's northern border.