Castanopsis borneensis is a tree in the family Fagaceae. The specific epithet Latin: borneensis is from the Latin, meaning 'of Borneo'.
Castanopsis borneensis grows as a tree up to 20m (70feet) tall with a trunk diameter of up to 30cm (10inches). The bark is smooth or fissured. The coriaceous leaves measure up to 11cm (04inches) long. Its ovoid nuts measure up to 21NaN1 long.
Castanopsis borneensis is endemic to Borneo. Its habitat is lowland dipterocarp and kerangas forests from sea-level to 200m (700feet) altitude.