The Battle of Cape Gloucester was a battle in the Pacific theater of World War II, which took place between late December 1943 and April 1944, on the island of New Britain, part of the Territory of New Guinea. The battle was a major part of Operation Cartwheel, the main Allied strategy in the South West Pacific Area and Pacific Ocean Areas during 1943–44, and it was the second World War II landing of the U.S. 1st Marine Division, after Guadalcanal.