| São Mateus River | |
| Source1 Location: | Santa Catarina state |
| Mouth: | Lava-Tudo River |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
The São Mateus River is a river of Santa Catarina state in southeastern Brazil. It is part of the Uruguay River basin and a tributary of the Lava-Tudo River.