A new species from the Fagaceae family, Castanopsis corallocarpus Tan & Strijk, is described from Royal Belum State Park in Peninsular Malaysia. Here, we provide technical illustrations, colour images and a description of its conservation status and the collecting locality, in addition to a comparative analysis with other species in the region. The solitary nut of C. corallocarpus has a morphologically unique cupule, lined with rows of thick coral-like spines not seen in other Castanopsis species.