| Jänisjoki, Yanisyoki | |
| Mouth: | Lake Ladoga |
| Mouth Coordinates: | 61.7094°N 30.9936°W |
| Subdivision Type1: | Countries |
| Length: | 70km (40miles) |
| Basin Size: | 3900km2 |
Jänisjoki (Russian: Янисйоки) is a river of Finland and Russia. It begins from the territory of Finland in the province of Northern Karelia, passes into the Republic of Karelia in Russia and flows there into Lake Ladoga. It is long, and has a drainage basin of . It is part of the Neva River basin in Finland and Russia that flows into the Gulf of Finland in St. Petersburg, Russia.