| Per Aru | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Sri Lanka |
| Subdivision Type2: | Province |
| Subdivision Name2: | Northern Province |
| Subdivision Type3: | Districts |
| Subdivision Name3: | Vavuniya, Mullaitivu |
| Length: | 32km (20miles) |
| Source1 Location: | Vavuniya District |
| Mouth: | Nanthi Lagoon |
| Basin Size: | 374km2 |
The 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.[1]