| Nay Aru | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Sri Lanka |
| Subdivision Type2: | Province |
| Subdivision Name2: | Northern Province |
| Subdivision Type3: | District |
| Subdivision Name3: | Mullaitivu District |
| Length: | 20km (10miles) |
| Source1 Location: | Mullaitivu District |
| Mouth: | Nai Aru Lagoon |
| Mouth Location: | Mullaitivu District |
| Basin Size: | 187km2 |
The Nay Aru (or Nai Aru) is a small river in Northern Province, Sri Lanka. The 20 km (12 mi) long river rises in south-east Mullaitivu District, before flowing north-east through Mullaitivu District. The river empties into Nai Aru Lagoon.[1]