| Per Aru | |
| River | |
| Country | Sri Lanka | 
|---|---|
| State | Northern Province | 
| District | Vavuniya District Mullaitivu District | 
| Source | Vavuniya District | 
| Mouth | Nanthi Kadal | 
| - elevation | 0 m (0 ft) | 
| Length | 32 km (20 mi) | 
| Basin | 374 km2 (144 sq mi) | 
Per Aru is a river in Northern Province, Sri Lanka. The river rises in northern Vavuniya District, before flowing north/north-east through Vavuniya District and Mullaitivu District. The river empties into Nanthi Kadal lagoon.