| Castelbiague | |
| Commune Status: | Commune |
| Arrondissement: | Saint-Gaudens |
| Canton: | Bagnères-de-Luchon |
| Insee: | 31114 |
| Postal Code: | 31160 |
| Mayor: | Henri Ribet[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Cagire Garonne Salat |
| Coordinates: | 43.0372°N 0.9253°W |
| Elevation M: | 376 |
| Elevation Min M: | 334 |
| Elevation Max M: | 702 |
| Area Km2: | 5.84 |
Castelbiague (in French pronounced as /kastɛlbjaɡ/; Occitan (post 1500);: Castèthviague) is a commune in the Haute-Garonne department in southwestern France.