The River Vuoksi (Finnish) or River Vuoksa (Russian standard transcription) runs in the northernmost part of the Karelian Isthmus, from Lake Saimaa in southeastern Finland flowing into Lake Ladoga in northwestern Russia. The river enters Lake Ladoga in two armlets, an older northern armlet at Priozersk (Käkisalmi/Keksholm) and since 1857 a new southern armlet entering 50 kilometers further southeast at Taipale.

The entire run of the river is 162 kilometers via the Priozersk armlet or 150 kilometers via the Taipale armlet. For most of its length, the river broadens out to a series of lakes bound together by shorter riverlike connections. The descent between Lake Saima and Lake Ladoga is 69 meters.

The River Vuoksi connects Lake Ladoga with central Finland, and was once an important route for trade and communication. A western armlet, which is now overgrown, was an alternative route for the Karelians to reach the Gulf of Finland when the River Neva was blocked by enemies.

The river is famous for the great rapids, for instance at Imatra and the village of Losevo. The junction of the River Vuoksi and Lake Sukhodolskoye is a traditional place for international kayak, canoe and catamaran competitions.

At the Industrial Revolution, power generated from Vuoksi's rapids made the Vuoksi region Finland's industrial center in the late 19th century. Since the Winter War (1940), the Karelian Isthmus belongs to Russia and only 13 kilometers of the river's length remains in Finland.

The river's surroundings, including the Korela Fortress (formerly: Käkisalmi/Keksholm), is a popular resort for Saint Petersburg's residents.