Kaiser-Wilhelmsland formed part of German New Guinea, the South Pacific protectorate of the German Empire. Named in honour of Wilhelm I, who reigned as German Emperor from 1871 to 1888, it included the northern part of present-day Papua New Guinea. From 1884 until 1920 the territory was a protectorate of the German Empire. Kaiser-Wilhelmsland, the Bismarck Archipelago, the northern Solomon Islands, the Caroline Islands, Palau, Nauru, the Northern Mariana Islands, and the Marshall Islands comprised German New Guinea.

German New Guinea consisted of the northeastern part of the island of New Guinea and several nearby island groups and was the first part of the German colonial empire. The mainland part of the territory, called Kaiser-Wilhelmsland, became a German protectorate in 1884. Other island groups were added subsequently. The Bismarck Archipelago, and the North Solomon Islands were declared a German protectorate in 1885. The Caroline Islands, Palau, and the Mariana Islands were bought from Spain in 1899. German New Guinea annexed the formerly separate German Protectorate of Marshall Islands, which also included Nauru, in 1906. German Samoa, though part of the German colonial empire, was not part of German New Guinea.