The battle for Milne Bay, fought from August to September 1942, was a crucial engagement in the Pacific War between the forces of Imperial Japan and the Allies, primarily Australia and the United States. Located in southeastern New Guinea, Milne Bay became a strategic target for Japanese expansion as they sought to establish a base to threaten Allied supply routes and to cut off Australia from U.S. support. The Japanese aimed to seize this crucial location following their successes in the early months of the Pacific War.

However, the battle at Milne Bay turned sour for the Japanese forces. The Allies, under the command of Major General Cyril Clowes, assembled troops that included Australian soldiers and American support units. Despite initial Japanese landings and progress, Allied reinforcements and effective defensive tactics led to fierce fighting. The Allies utilized local knowledge of the terrain, night engagements, and coordinated air ground operations, ultimately leading to a stinging defeat for the Japanese.

By September 5, the circumstances on the ground compelled the Japanese high command to order a withdrawal, marking the first major defeat of Japanese ground forces in the Pacific Theater. The retreat was disorganized, and many troops suffered heavy losses during the evacuation. This defeat not only altered the momentum in the Pacific but also boosted Allied morale and demonstrated that Japanese forces were vulnerable to effective and coordinated opposition.