| Santo Antônio River | |
| Source1 Location: | Espírito Santo state |
| Mouth: | Braço Sul do Rio Itaúnas |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
The Santo Antônio River is a river of Espírito Santo state in eastern Brazil. It is a tributary of the Braço Sul do Rio Itaúnas.