| Sededema | |
| Other Name: | Седедема / Сэдэдэмэ |
| Source1 Location: | Alazeya Plateau |
| Mouth: | Kolyma |
| Mouth Coordinates: | 67.0938°N 153.0278°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Russia |
| Length: | 567km (352miles) |
| Basin Size: | 18500km2 |
| Pushpin Map: | Russia Sakha Republic |
| Pushpin Map Caption: | Mouth location in Yakutia, Russia |
The Sededema (Russian: Седедема; Yakut: Сэдэдэмэ, Sededeme) is a river in Sakha Republic, Russia. It is a left tributary of the Kolyma. It is long, and has a drainage basin of .