| Castet | |
| Commune Status: | Commune |
| Arrondissement: | Oloron-Sainte-Marie |
| Canton: | Oloron-Sainte-Marie-2 |
| Insee: | 64175 |
| Postal Code: | 64260 |
| Mayor: | Robert Daguerre[1] |
| Term: | 2023 - 2026 |
| Intercommunality: | Vallée d'Ossau |
| Coordinates: | 43.07°N -0.4158°W |
| Elevation M: | 493 |
| Elevation Min M: | 419 |
| Elevation Max M: | 2020 |
| Area Km2: | 23.53 |
Castet (pronounced as /fr/; oc-gascon|Castèth) is a commune in the Pyrénées-Atlantiques department in south-western France. It lies on the river Gave d'Ossau, in the Ossau Valley. The Lac de Castet is an artificial lake in Castet, created by a dam in the Gave d'Ossau.