| Mont-Saint-Jean | |
| Commune Status: | Commune |
| Arrondissement: | Vervins |
| Canton: | Hirson |
| Insee: | 02522 |
| Postal Code: | 02360 |
| Mayor: | Patrick Feuillet[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CC Trois Rivières |
| Coordinates: | 49.7906°N 4.2078°W |
| Elevation M: | 243 |
| Elevation Min M: | 192 |
| Elevation Max M: | 266 |
| Area Km2: | 3.95 |
Mont-Saint-Jean (in French pronounced as /mɔ̃ sɛ̃ ʒɑ̃/) is a commune in the Aisne department in Hauts-de-France in northern France.