| Le Moustoir | |
| Native Name: | Ar Vouster |
| Commune Status: | Commune |
| Coordinates: | 48.2664°N -3.5008°W |
| Insee: | 22157 |
| Postal Code: | 22340 |
| Arrondissement: | Guingamp |
| Canton: | Rostrenen |
| Mayor: | Cédric Le Moroux[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Poher Communauté |
| Elevation Min M: | 98 |
| Elevation Max M: | 192 |
| Area Km2: | 14.85 |
Le Moustoir (in French pronounced as /lə mustwaʁ/; Breton: Ar Vouster) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.
Inhabitants of Le Moustoir are called moustoiriens in French.