Vachellia abyssinica (flat top acacia) is a tree up to 16 m tall. Its bark is reddish-brown on older trees. On younger trees it is pale yellowish-brown, peeling off in papery wads. Young twigs are softly hairy. Thorns are aligned in straight pairs at nodes. Leaves are in pinnae pairs of 20-40; the leaflets are very small, up to 4 × 0.75 mm. The inflorescence is arranged in white spherical heads. The involucel is located in the lower half of the peduncle. Seed pods are dehiscent.