New Guinea Force was a military command unit for Australian, United States and native troops from the Territories of Papua and New Guinea serving in the New Guinea campaign during World War II. Formed in April 1942, when the Australian First Army was formed from the Australian I Corps after it returned from the Middle East, it was responsible for planning and directing all operations within the territory up until October 1944. General Headquarters Southwest Pacific Area Operational Instruction No.7 of 25 May 1942, issued by Commander-Allied-Forces, General Douglas MacArthur, placed all Australian and US Army, Air Force and Navy Forces in the Port Moresby Area under the control of New Guinea Force. Over the course of its existence, New Guinea Force was commanded by some of the Australian Army's most notable commanders, including Sydney Rowell, Sir Edmund Herring and Sir Leslie Morshead.

The New Guinea campaign of the Pacific War lasted from January 1942 until the end of the war in August 1945. During the initial phase in early 1942, the Empire of Japan invaded the Territory of New Guinea on 23 January and Territory of Papua on 21 July and overran western New Guinea beginning on 29 March. During the second phase, lasting from late 1942 until the Japanese surrender, the Allies—consisting primarily of Australian forces—cleared the Japanese first from Papua, then New Guinea, and finally from the Dutch colony.