The Battle of Cape Gloucester was a battle in the Pacific theater of World War II between Japanese and Allied forces which took place on the island of New Britain, Territory of New Guinea, between late December 1943 and April 1944. 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 was the second World War II landing of the U.S. 1st Marine Division, after Guadalcanal.