| Longavesnes | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Longavesnes 80.svg |
| Arrondissement: | Péronne |
| Canton: | Péronne |
| Insee: | 80487 |
| Postal Code: | 80240 |
| Mayor: | Xavier Wauters[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Haute Somme |
| Coordinates: | 49.9717°N 3.0603°W |
| Elevation M: | 100 |
| Elevation Min M: | 94 |
| Elevation Max M: | 144 |
| Area Km2: | 4.09 |
Longavesnes (in French pronounced as /lɔ̃ɡavɛn/) is a commune in the Somme department in Hauts-de-France in northern France.
Longavesnes is situated 13miles northwest of Saint-Quentin, in the northeast corner of the department, on the D101 road.