| Deduru Oya | |
| Pushpin Map: | Sri Lanka |
| Length: | 142km (88miles) |
| Source1 Location: | Kurunegala District |
| Mouth Location: | Chilaw |
| Mouth Elevation: | Sea level |
| Basin Size: | 2620km2 |
The Deduru Oya is the sixth-longest river of Sri Lanka. The 1420NaN0 long river runs across four provinces and five districts.
Its catchment area receives approximately 4,313 million cubic metres of rain per year, and approximately 27 percent of the water reaches the sea. It has a catchment area of 2,620 square kilometres.[1]