The Kara Sea (Russian: Ка́рское мо́ре) is part of the Arctic Ocean (in the area sometimes called the Arctic Mediterranean Sea) off northern Siberia, bound by the Kara Strait (West, connecting to the Barents Sea) and the Severnaya Zemlya Islands and the Northern Land Archipelago (East, and the Laptev Sea).

It is roughly 1,450 kilometres long and 970 kilometres wide with an area of around 880,000 km² and a mean depth of 110 m.

The Kara receives a large amount of fresh water from the Ob, Yenisei, Pyasina , and Taimyra rivers, so its salinity is very variable.

Its main ports are Novyy Port and Dikson and it is important as a fishing ground although the sea is ice-bound for all but two months of the year. There is the possibility of significant reserves of oil or natural gas beneath the sea, but this has yet to be confirmed (2001).

There is concern about the levels of nuclear waste the Russians have dumped in the sea and the effect this will have on the marine environment.