The Beaufort Sea is a large body of water north of The Northwest Territories, the Yukon, and Alaska and west of Canada's arctic islands that is a part of the Arctic Ocean. Its northwestern boundary is defined by a line connecting Point Barrow, Alaska, and Lands End Prince Patrick Island. It is about 450 000 square kilometers in area. The sea is named after British hydrographer Sir Francis Beaufort.

The large Mackenzie River empties into the sea as do other smaller rivers. It is an important habitat for whales and sea birds and is still relatively untouched by commercial traffic.

There is an ongoing dispute between Canada and the United States over the delimitation of part of the maritime section of the International Boundary in the Beaufort Sea.

The Beaufort Sea is also the location of what are believed to be significant petroleum reserves beneath the seabed, a continuation of proven reserves in the nearby Mackenzie River and North Slope. The Beaufort Sea was first explored in the 1960s and the Amauligak Project of 1986 began operating the first functioning oil platform.

The entire Beaufort Sea is totally frozen during much of the year. The permanent ice-pack covers the northern edge of the Beaufort Sea year-round.