Erythrostemon gilliesii grows to 1–4 m , depending on rainfall. The leaves are bipinnate, 10–15 cm long, bearing 3–10 pairs of pinnae, each with 6–10 pairs of leaflets 5–6 mm long and 2–4 mm broad. The flowers are borne in racemes up to 20 cm long, each flower with five yellow petals with 10 long conspicuous red stamens. The pods are densely covered in short, red glandular hairs.