Castanopsis borneensis is a species of tree in the family Fagaceae. The specific epithet is from the Latin, meaning 'of Borneo'.
Description Castanopsis borneensis grows as a tree up to tall with a trunk diameter of up to . The bark is smooth or fissured. The coriaceous leaves measure up to long. Its ovoid nuts measure up to long.
Distribution and habitat Castanopsis borneensis is endemic to Borneo. Its habitat is lowland dipterocarp and kerangas forests, to altitude.
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