| Sadu | |
| Pushpin Map: | Romania |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Gorj County |
| Length: | 22km (14miles) |
| Source1: | Parâng Mountains |
| Mouth: | Jiu |
| Mouth Location: | Bumbești-Jiu |
| Mouth Coordinates: | 45.1835°N 23.3826°W |
| Basin Size: | 22km2 |
| Tributaries Left: | Zănoaga, Sădișor |
| Tributaries Right: | Sadul lui Sân, Alunul |
The Sadu is a left tributary of the river Jiu in Romania. It discharges into the Jiu in Bumbești-Jiu.[1] Its length is 22km (14miles) and its basin size is 22km2.