| Masin Secondary School | |
| Native Name: | Sekolah Menengah Masin |
| Postcode: | BH2723 |
| Coordinates: | 4.8399°N 114.8414°W |
| District: | Cluster 2 |
| Principal: | Cikgu Ivan Moore |
| Grades: | Years 7-11 |
Masin Secondary School is a government secondary school located in Masin, a village in Brunei-Muara District, Brunei. The school provides five years of secondary education, leading up to GCE 'O' Level examination.