| Jaci Paraná River | |
| Pushpin Map: | Brazil |
| River System: | Madeira River |
| Source1 Location: | Rondônia state |
| Mouth Coordinates: | -9.2157°N -64.3856°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
| Tributaries Left: | Formoso River |
| Tributaries Right: | Branco River |
The Jaci Paraná River (Portuguese: Rio Jaci Paraná) is a river of Rondônia state in western Brazil.It is a tributary of the Madeira River, which it joins at Jaci Paraná in the municipality of Porto Velho, Rondônia
Tributaries of the Jaci Paraná river basin rise in the Guajará-Mirim State Park, created in 1990.The river forms the western boundary of the Jaci Paraná Extractive Reserve, created in 1996.