| Monclar-sur-Losse | |
| Commune Status: | Commune |
| Arrondissement: | Mirande |
| Canton: | Pardiac-Rivière-Basse |
| Insee: | 32265 |
| Postal Code: | 32300 |
| Mayor: | Benoît Laprebende[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Cœur d'Astarac en Gascogne |
| Coordinates: | 43.5325°N 0.3339°W |
| Elevation M: | 169 |
| Elevation Min M: | 164 |
| Elevation Max M: | 267 |
| Area Km2: | 10.47 |
Monclar-sur-Losse (pronounced as /fr/, literally Monclar on the Osse; oc|Montclar sus l'Òssa) is a commune in the Gers department in southwestern France.