The Battle of Cape Gloucester was fought in the Pacific theater of World War II between Japanese and Allied forces on the island of New Britain, Territory of New Guinea, between 26 December 1943 and 16 January 1944. Codenamed Operation Backhander, the US landing formed part of the wider Operation Cartwheel, the main Allied strategy in the South West Pacific Area and Pacific Ocean Areas during 1943–1944. It was the second landing the US 1st Marine Division had conducted during the war thus far, after Guadalcanal. The objective of the operation was to capture the two Japanese airfields near Cape Gloucester that were defended by elements of the Japanese 17th Division.

The 1st Marine Division is a Marine division of the United States Marine Corps headquartered at Marine Corps Base Camp Pendleton, California. It is the ground combat element of the I Marine Expeditionary Force.