| Castelnau-Montratier | |
| Commune Status: | Commune |
| Arrondissement: | Cahors |
| Canton: | Marches du Sud-Quercy |
| Insee: | 46063 |
| Postal Code: | 46170 |
| Mayor: | Dominique Marin[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Quercy Blanc |
| Coordinates: | 44.27°N 1.354°W |
| Area Km2: | 84.76 |
Castelnau-Montratier (in French pronounced as /kastɛlno mɔ̃ʁatje/; before 2024: Castelnau-Montratier-Sainte-Alauzie; Languedocien: Castèlnau de Montratièr e Senta Alàusia) is a commune in the department of Lot, southern France. The municipality was established on 1 January 2017, by the merger of the former communes of Castelnau-Montratier (the seat) and Sainte-Alauzie.[2]