Cycas brunnea is a species of cycad in the genus Cycas, native to northern Australia in northwest Queensland and northeast Northern Territory in a small area straddling the border of the two regions. It occurs on exposed sites in savanna and creek valleys on sandstone and limestone derived soils, with moderate seasonal rainfall. The stems grow to 2–5 m tall, with numerous leaves in the crown. The leaves are 1.2-1.7 m long, glabrous with age, pinnate, with 160-240 leaflets, the leaflets 17–27 cm long and 6-7.5 mm wide. The petioles are covered in brown tomentum and armed with sharp spines.