Mount Tambuyukon, Mountain summit in Sabah, Malaysia.

Mount Tambuyukon is a 2,579-metre mountain on the borders of Ranau, Kota Belud and Kota Marudu districts in Sabah, Malaysia. Its broad, rounded summit is covered in low, densely packed woody vegetation, with no exposed rock face or path visible. The mountain lies north of Mount Kinabalu and is part of the Wariu Formation.

Mount Tambuyukon lies on the Wariu Formation, shared with Mount Kinabalu. Pleistocene glacial tills and glaciated summit plateaus in the Kinabalu area, including similar deposits near Tambuyukon, indicate that its summit was significantly higher than other parts of the Crocker Range during the Pleistocene. During British colonial rule, the mountain was known as Gunung Nombuyukung; the name Tembayukan was recorded by British forces after Gurkha soldiers' pronunciation, later standardised as Tambuyukon.

Villages around the mountain know it as Gunung Nombuyukung, a name recorded in Kg. Lampaki, Kg. Monggis, Kg. Pinawantai, Kg. Pahu and Kg. Togop in Ranau district, and in Kg. Marak-parak, Kg. Molangkap, Kg. Pomoitan and Kg. Tangkol in Kota Marudu. The Dusun form Nulu Tambuyukon is also recorded. The present spelling comes from the British colonial register, which wrote Gunung Tembayukan after the pronunciation of Gurkha soldiers.

Two climbing trails start from Monggis village in Kota Marudu district, one from the village itself and one from the Sabah Parks substation there, near the Ranau border. A permit from the park authority must be obtained before climbing. The summit area lies within the Kinabalu National Park forest reserve, in Ranau district.

A 2012–2013 mammal survey from 300 metres to the summit recorded 44 mammal species and only the second known population of the summit rat, the first having been found on Mount Kinabalu. The survey covered the mountain's full elevational range.