The Barents Sea (Norwegian: Barentshavet, Russian: Баренцево море or Barentsevo More) is a marginal sea of the Arctic Ocean, located north of Norway and Russia. Known in the Middle Ages as the Murman Sea, the sea takes its current name from the Dutch navigator Willem Barents. It is a rather deep shelf sea (average depth 760 feet (230 m) and maximum depth 1,480 feet (450 m)), bordered by the shelf edge towards the Norwegian Sea in the west, the islands of Svalbard (Norway) in the northwest, and the islands of Franz Josef Land and Novaya Zemlya (Arkhangelsk Oblast) in the northeast and east. Novaya Zemlya separates the Kara Sea from the Barents Sea. Significant fossil fuel energy resources exist in the Barents Sea region.

The southern half of the Barents Sea, including the ports of Murmansk (Russia) and Vardø (Norway) remain ice-free year round due to the warm North Atlantic drift. In September, the entire Barents Sea is more or less completely ice-free. Until the Winter War (1939–40), Finland's territory also reached to the Barents Sea, with the harbor at Petsamo being Finland's only ice-free winter harbor.