New Britain (Tok Pisin: Niu Briten) is the largest island in the Bismarck Archipelago, part of the Islands Region of Papua New Guinea. It is separated from New Guinea by a northwest corner of the Solomon Sea (or with an island hop of Umboi the Dampier and Vitiaz Straits) and from New Ireland by St. George's Channel. The main towns of New Britain are Rabaul/Kokopo and Kimbe. The island is roughly the size of Taiwan. While the island was part of German New Guinea, it was named Neupommern ("New Pomerania").

In common with most of the Bismarcks it was largely formed by volcanic processes, and has active volcanoes including Ulawun (highest volcano nationally), Langila, the Garbuna Group, the Sulu Range, and the volcanoes Tavurvur and Vulcan of the Rabaul caldera. A major eruption of Tavurvur in 1994 destroyed the East New Britain provincial capital of Rabaul. Most of the town still lies under metres of ash, and the capital has been moved to nearby Kokopo.