| Martinvast | |
| Commune Status: | Commune |
| Arrondissement: | Cherbourg |
| Canton: | Cherbourg-en-Cotentin-3 |
| Insee: | 50294 |
| Postal Code: | 50690 |
| Mayor: | Jacky Marie[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CA Cotentin |
| Coordinates: | 49.5967°N -1.6628°W |
| Elevation M: | 58 |
| Area Km2: | 10.31 |
Martinvast (pronounced as /fr/) is a commune on the Cotentin peninsula in the Manche department in Normandy in north-western France.