| Do Sono River | |
| Name Other: | Rio do Sono |
| Pushpin Map: | Brazil |
| Source1 Location: | Tocantins state |
| Source1 Coordinates: | -10.1821°N -46.9361°W |
| Mouth Location: | Tocantins River, Pedro Afonso, Tocantins |
| Mouth Coordinates: | -8.9598°N -48.176°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
| Tributaries Left: | Novo River |
| Tributaries Right: | Soninho River |
The Do Sono River (Portuguese: Rio do Sono) is a river of Tocantins state in central Brazil. It is a right tributary of the Tocantins River.
The river has its headwater in the Jalapão State Park, a fully protected conservation unit created in 2001.It forms where the Novo and Soninho meet on the northwest boundary of the state park.