Castanopsis oviformis is a tree in the family Fagaceae. The specific epithet oviformis means 'egg-shaped', referring to the cupule.
Castanopsis oviformis grows as a tree up to 30m (100feet) tall with a trunk diameter of up to 50cm (20inches). The brownish bark is scaly or cracked. The coriaceous leaves measure up to 14cm (06inches) long. Its ovoid nuts measure up to 2.51NaN1 long and are considered edible.
Castanopsis oviformis is endemic to Borneo. Its habitat is hill dipterocarp and kerangas forests up to 900m (3,000feet) elevation.