Chukchi Sea (Russian: Чуко́тское мо́ре; IPA: [tɕʊˈkotskəjə ˈmorʲə]) is a marginal sea of the Arctic Ocean. It is bounded on the west by the De Long Strait, off Wrangel Island, and in the east by Point Barrow, Alaska, beyond which lies the Beaufort Sea. The Bering Strait forms its southernmost limit and connects it to the Bering Sea and the Pacific Ocean. The principal port on the Chukchi Sea is Uelen in Russia. The International Date Line crosses the Chukchi Sea from NW to SE. It is displaced eastwards to avoid Wrangel Island as well as the Chukotka Autonomous Okrug on the Russian mainland.

The sea has an approximate area of 595,000 km² (230,000 mi²) and is only navigable about four months of the year. The main geological feature of the Chukchi Sea bottom is the 700 km (435 mi)-long Hope Basin, which is bound to the northeast by the Herald Arch. Depths less than 50 m (164 ft) occupy 56% of the total area.

The Chukchi Sea has very few islands compared to other seas of the Arctic. Wrangel Island lies at the northwestern limit of the sea, Herald Island is located near its northern limit, and a few small islands lie along the Siberian and Alaskan coasts.

The Chukchi, or Chukchee (Russian: чукчи (plural), чукча (singular)) are an indigenous people inhabiting the Chukchi Peninsula and the shores of the Chukchi Sea and the Bering Sea region of the Arctic Ocean within the Russian Federation. They speak the Chukchi language. The Chukchi originated from the people living around the Okhotsk Sea.

The majority of Chukchi reside within Chukotka Autonomous Okrug, but some also reside in the neighboring Sakha Republic to the west, Magadan Oblast to the southwest, and Koryak Autonomous Okrug to the south. Some Chukchi also reside in other parts of Russia, as well as in Europe and North America. The total number of Chukchi in the world slightly exceeds 15,000.

The Chukchi are traditionally divided into the Maritime Chukchi, who had settled homes on the coast and lived primarily from sea mammal hunting, and the Reindeer Chukchi, who nomadised in the inland tundra region with their herds of reindeer. The Russian name "Chukchi" is derived from the Chukchi word Chauchu ("rich in reindeer"), which was used by the 'Reindeer Chukchi' to distinguish themselves from the 'Maritime Chukchi,' called Anqallyt ("the sea people"). The indigenous name for a member of the Chukchi ethnic group as a whole is Luoravetlan (literally 'true person').