| Seidewitz | |
| Source1 Location: | Eastern Ore Mountains |
| Mouth Location: | Gottleuba |
| Mouth Coordinates: | 50.9545°N 13.9373°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | State |
| Subdivision Name2: | Saxony |
The Seidewitz is a river of Saxony, Germany. It is a left tributary of the Gottleuba, into which it flows in the town Pirna. Its source is in the Eastern Ore Mountains, near the village Breitenau. It flows through the town Liebstadt. Its length is about .