Netherlands New Guinea was a Dutch territory on the western side of New Guinea, until 1969, when it became part of Indonesia as Irian Jaya. Until 1949, Netherlands New Guinea was next to, though governed separately to, the Netherlands East Indies, but when this gained independence as Indonesia, Netherlands New Guinea remained Dutch.

After an armed conflict in the early 1960s, the Dutch agreed to place the territory under United Nations control. A plebiscite was to be held to vote on the topic of joining Indonesia before 1970. After this took place in 1969, the territory formally became part of Indonesia, renaming it to Irian Jaya in 1973.