This list of highest mountains of New Guinea shows all mountains on the island of New Guinea that are at least 3750 m high and have a topographic prominence of 500 m or more. These c. 50 peaks are also the highest mountains of Australasia, where, outside New Guinea, the highest mountain is Aoraki / Mount Cook in New Zealand with a height of 3724 m. A list of highest mountains of Oceania with the same limitations is almost identical, with the addition of the Hawaiian volcanoes of Mauna Kea (4205 m) and Mauna Loa (4169 m) in 18th and 20th positions. The list also shows the 36 highest thus defined mountains of Indonesia, except for the 3805 m high Gunung Kerinci on Sumatra (#29 in Indonesia), and the 16 highest mountains of Papua New Guinea.
Many mountains in New Guinea are poorly surveyed and some major summits remain unnamed on maps. Even well measured mountains have conflicting heights on otherwise authoritative maps. For example, the highest point in Oceania, Carstensz Pyramid, was established to be 4884 m in 1973 when an Australian survey expedition put a beacon on the summit. This corresponded closely to the 4866 m estimate by the first Lorentsz Expedition in 1910 using repeated theodolite observations from the south coast. However, over time the mountain had grown in stature: measurements from northern observation peaks for the highest summit (each time Ngga Pulu) were 5000 m in 1910 by Ludolph Doorman and 5030 m in 1926 by Charles C.F.M. Le Roux. The 1936 Carstensz Expedition using barometric and boiling point measurements on the summit of Ngga Pulu also derived an elevation of 5030 m. After ascending the Pyramid in 1962, Heinrich Harrer even estimated that peak to be 17,096 feet or 5211 m high. The 1973 survey established that the 1936 barometric estimates were consistently between 118 and 127 m too high. Nevertheless, the 5030 m height is still prevalent in most atlases and maps.