| Gagnac-sur-Garonne | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Gagnac-sur-Garonne (Haute-Garonne).svg |
| Arrondissement: | Toulouse |
| Canton: | Castelginest |
| Insee: | 31205 |
| Postal Code: | 31150 |
| Mayor: | Michel Simon[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Toulouse Métropole |
| Coordinates: | 43.6997°N 1.3764°W |
| Elevation M: | 103 |
| Elevation Min M: | 113 |
| Elevation Max M: | 123 |
| Area Km2: | 4.34 |
Gagnac-sur-Garonne (in French pronounced as /ɡaɲak syʁ ɡaʁɔn/, literally Gagnac on Garonne; Occitan (post 1500);: Ganhac de Garona) is a commune in the Haute-Garonne department in southwestern France.