| Lavau-sur-Loire | |
| Native Name: | (Gallo) |
| Commune Status: | Commune |
| Arrondissement: | Saint-Nazaire |
| Canton: | Blain |
| Insee: | 44080 |
| Postal Code: | 44260 |
| Mayor: | Claire Tramier[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Estuaire et Sillon |
| Coordinates: | 47.3078°N -1.9653°W |
| Elevation Min M: | 0 |
| Elevation Max M: | 15 |
| Area Km2: | 16.22 |
Lavau-sur-Loire (in French pronounced as /lavo syʁ lwaʁ/, literally Lavau on Loire; Gallo: Lavau or Lavao, Breton: Gwal-Liger) is a commune in the Loire-Atlantique department in western France.