Aloe aculeata is easily identified from other similar species by the conspicuous tubercle of spines on the leaves. Aloe peglerae is often confused with Aloe aculeata when not in flower, but the presence of thorns on the leaf surface is an exclusive feature of Aloe peglerae .

It has a single rosette up to 1 meter high and wide. The leaves are long and fairly broad at the base, 120 mm wide, and are green in color, curved inward giving the rosette a rounded appearance. The leaf margin is armed with reddish brown triangular teeth. A distinctive feature of the leaf is the presence of numerous spines on the surface. In some species the thorn is a different color from the surrounding tissue, giving the plant a mottled appearance.

In young plants the inflorescence is unique, since the plant matures in May and is divided into three or four branches. Each cluster is long and narrow and gradually decreases at the tip. The flowers are tubular in shape, about 40 mm long, ranging in color from yellow to orange-reddish. Some specimens are uniform in color while others are bicolour. It blooms from May to July (in the northern hemisphere).