The Landing at Nassau Bay was an amphibious landing by Allied forces at Nassau Bay during the New Guinea campaign of World War II that took place between 30 June and 6 July 1943. The operation was undertaken so that Allies could secure a beachhead to establish a supply point to shorten their supply lines for the proposed attack on Salamaua as part of the Salamaua–Lae campaign and resulted in a battalion-sized force of US infantry and supporting elements being landed largely unopposed on the south-eastern flank of the battle zone.

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.