| Sandakan District Mosque | |
| Native Name: | Masjid Daerah Sandakan |
| Native Name Lang: | ms |
| Map Type: | Malaysia Sabah |
| Map Size: | 220px |
| Coordinates: | 5.8463°N 118.1291°W |
| Religious Affiliation: | Islam |
| Location: | Sandakan, Sabah, Malaysia |
| Tradition: | Sunni |
| Festivals: | --> |
| Organizational Status: | --> |
| Architect: | Dato Baharuddin Kassim |
| Architecture Type: | mosque |
| Groundbreaking: | 1985 |
| Year Completed: | 1989 |
| Date Destroyed: | --> |
| Minaret Quantity: | 1 |
| Elevation Ft: | --> |
The Sandakan District Mosque (Malay: Masjid Daerah Sandakan or also known as Masjid Besar Sim-Sim) is a mosque in Sandakan, Sabah, Malaysia. Built in 1985 and completed in 1989, it is the main mosque for the district of Sandakan. The mosque was officially opened in 1990.[1]
In 2016, the mosque was visited by the Crown Prince of Perlis, Tuanku Syed Faizuddin Putra Jamalullail.[2]