| Si Ma Cai | |
| Settlement Type: | Township (Class-5) |
| Official Name: | Si Ma Cai township |
| Native Name: | Thị trấn Si Ma Cai |
| Pushpin Map: | Vietnam |
| Subdivision Type: | Country |
| Subdivision Type1: | Region |
| Subdivision Name1: | Northwest |
| Subdivision Type2: | Province |
| Subdivision Name2: | Lào Cai |
| Subdivision Type3: | District |
| Subdivision Name3: | Si Ma Cai |
| Unit Pref: | Imperial |
| Timezone: | UTC + 7 |
| Utc Offset: | +7 |
| Coordinates: | 22.6914°N 104.2756°W |
Si Ma Cai is a township (Vietnamese: thị trấn) and capital of Si Ma Cai District, Lào Cai Province, Vietnam.[1]