Xanthophyllum brachystachyum is a tree in the family Polygalaceae. The specific epithet ' is from the Greek meaning 'short spike', referring to the shortness of the inflorescence.
Xanthophyllum brachystachyum grows up to tall with a trunk diameter of up to . The smooth bark is grey-green or whitish. The flowers are purplish, drying orange-brown. The pale brown fruits are round and measure up to in diameter.
Xanthophyllum brachystachyum is endemic to Borneo. Its habitat is mixed dipterocarp forests from to altitude.