| Ivaí River | |
| Pushpin Map: | Brazil |
| Source1 Location: | Paraná state |
| Mouth Location: | Paraná River |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
| Length: | 798km (496miles)[1] |
| Discharge1 Avg: | (Period: 1974-2008)733.4m3/s[2] |
| Basin Size: | 36587km2[3] |
| Discharge1 Location: | mouth |
The Ivaí River (Portuguese, Rio Ivaí) is a river of Paraná state in southern Brazil. It is a tributary of the Paraná River. Its official spelling is Ivaí, with variants including Ivahy and Ival.[4]
The river basin is ecologically very degraded, with fragile and vulnerable soil. It contains the Perobas Biological Reserve, a strictly protected conservation unit created in 2006.