Gonystylus micranthus grows as a tree up to 25 metres (82 ft) tall, with a trunk diameter of up to 60 centimetres (24 in). Bark is dark brown. The fruit is dark brown, up to 4 centimetres (1.6 in) long. Its habitat is forest from sea-level to 100 metres (330 ft) altitude. G. micranthus is endemic to Borneo.