| Saint-Martin-de-Castillon | |
| Image Coat Of Arms: | Blason ville fr Saint-Martin-de-Castillon (Vaucluse).svg |
| Arrondissement: | Apt |
| Canton: | Apt |
| Insee: | 84112 |
| Postal Code: | 84750 |
| Mayor: | Charlotte Carbonnel[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Pays d'Apt-Luberon |
| Coordinates: | 43.8603°N 5.5125°W |
| Elevation M: | 486 |
| Elevation Min M: | 268 |
| Elevation Max M: | 1072 |
| Area Km2: | 38.21 |
Saint-Martin-de-Castillon (in French pronounced as /sɛ̃ maʁtɛ̃ də kastijɔ̃/; Occitan (post 1500);: Sant Martin de Castilhon) is a commune in the Vaucluse department in the Provence-Alpes-Côte d'Azur region in southeastern France.
The river Calavon flows westward through the middle of the commune and forms part of its western border.