| Oijärvi | |
| Coords: | 65.6333°N 79°W |
| Inflow: | Kivijoki |
| Pushpin Map: | Finland |
| Outflow: | Oijärvi Canal |
| Catchment: | Kuivajoki |
| Basin Countries: | Finland |
| Area: | 21.049km2 |
| Depth: | 1.11m (03.64feet) |
| Max-Depth: | 2.42m (07.94feet) |
| Volume: | 0.0234km3 |
| Shore: | 60.26km (37.44miles) |
| Elevation: | 89.8m (294.6feet) |
| Frozen: | December–May |
Oijärvi is a medium-sized lake of northern Finland in the Kuivajoki main catchment area. It is located in the Northern Ostrobothnia region and Ii municipality.[1] A big part of the lake belongs to the Natura 2000 protection program due to its good environment for birds.[2]