| Oetternbach | |
| Mouth Location: | Bega |
| Mouth Coordinates: | 52.024°N 8.8245°W |
| Subdivision Type1: | Country |
| Subdivision Type2: | State |
| Length: | 16.6km (10.3miles) |
Oetternbach is a river of North Rhine-Westphalia, Germany. It is a left tributary of the Bega west of Lemgo.