Walsura pachycaulon is a tree in the family Meliaceae. The specific epithet pachycaulon means 'thick stems', referring to the leaf stems.
Walsura pachycaulon grows up to 29m (95feet) tall, with a diameter of up to . The bark is black to brown. The leaves are oblong to elliptic to oblanceolate and measure up to long. The round fruits are brown.
Walsura pachycaulon is endemic to Borneo. Its habitat is hill and lowland forests to elevations of about .