Castanopsis endertii is a tree in the family Fagaceae. It is named for the Dutch botanist and plant collector Frederik Endert.
Castanopsis endertii grows as a tree up to tall with a trunk diameter of up to . The brownish bark is slightly fissured with ring-like features. The coriaceous leaves measure up to long. Its roundish, edible nuts measure up to long.
Castanopsis endertii is endemic to Borneo. Its habitat is montane forests up to elevation.