| Official Name: | Qaleh-ye Mohammad Aqa |
| Native Name: | قلعه محمد آقا |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Semnan |
| Subdivision Type2: | County |
| Subdivision Name2: | Shahrud |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Bastam |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Kharqan |
| Population As Of: | 2006 |
| Population Total: | 182 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.6236°N 55.05°W |
Qaleh-ye Mohammad Aqa (Persian: قلعه محمد آقا, also Romanized as Qal‘eh-ye Moḩammad Āqā; also known as Kalāteh-ye Moḩammad Āqā) is a village in Kharqan Rural District, Bastam District, Shahrud County, Semnan Province, Iran. At the 2006 census, its population was 182, in 51 families.