Castanopsis microphylla is a tree in the family Fagaceae. The specific epithet Greek, Modern (1453-);: microphylla is from the Greek meaning 'small-leaved'.
Castanopsis microphylla grows as a tree up to 30m (100feet) tall with a trunk diameter of up to 60cm (20inches). The bark is smooth, occasionally flaky. The coriaceous leaves measure up to 8cm (03inches) long. Its ovoid nuts measure up to 1.51NaN1 long.
Castanopsis microphylla is endemic to Borneo. Its habitat is lowland dipterocarp to lower montane forests up to 1600m (5,200feet) elevation.