The Bougainville campaign was a series of land and naval battles of the Pacific campaign of World War II between Allied forces and the Empire of Japan, named after the island of Bougainville. It was part of Operation Cartwheel, the Allied grand strategy in the South Pacific.

Bougainville Island is the main island of the Autonomous Region of Bougainville, which is part of Papua New Guinea. Its land area is 9,300 km2 (3,600 sq mi). The population of the whole province, including nearby islets such as the Carterets, is approximately 300,000. The highest point is Mount Balbi, on the main island, at 2,715 m (8,907 ft).