Acacia seyal is a small to medium-sized tree, growing to 17 m tall and 60 cm in diameter at breast height; crown is umbrella shaped, resembling that of A. tortilis. A characteristic feature of the tree is its rust-coloured powdery bark; A. seyal var. fistula has whitish bark. Large, straight spines occur on the branches, and smaller, curved thorns are present near the tips of the branches. Leaves bipinnate, dark green, 4-12 pairs of pinnae, 10-12 pairs of leaflets each 1-2 x 4-12 mm. Flowers clustered in shining, yellow, globose heads, 1.5 cm diameter, on stems 3 cm long. Pods 10-15 x 1 cm, slightly curved, light brown when mature and indehiscent, containing 6-10 seeds. Seeds are elliptic (5-6 x 2.5-3.5 mm ), olive-brown branches. The generic name ‘acacia’ comes from the Greek word ‘akis’, meaning ‘point’ or ‘barb’.