Aloe howmanii is a cliff-hanging shrublet, branching from the base and forming loose clusters of up to 10 heads, with branches up to 300 mm long. The lower stems are whitish grey, 12–14 mm in diameter. The leaves are succulent and sometimes almost rounded (subterete) and clasping (amplexicaul) at the base. They grow in 2 opposite rows (distichous), forming a fan. Each head usually has 4 functional leaves. The leaves of cultivated plants can be up to as much as 12, and 150–250 × 12–18 mm, becoming reddish and deciduous from below. The leaves are linear, slightly tapering, and slightly sickle-shaped; the upper surface is green, rounded (convex to slightly convex); the margins translucent (a 1.5 mm band) and with minute teeth (denticulate), the teeth are 2–4 mm apart; the lower surface is convex, the apex obtuse to subacute, cuspidate.

The inflorescence is simple 200–450 mm long, bending upwards, with the raceme erect, 40–120 mm long, sometimes almost in a head (subcapitate), bearing 12–45 flowers, the buds ascending, open flowers pendent. The bracts are ovate-acute, 3–6 × 2–4 mm, 3-nerved. The flower stalks are 10–15 mm long, orange. The flower (perianth) is orange-red, 24–25 × 7 mm, with a short stipe. The petals (tepals) are fused into a tube, 7 mm in diameter, green-tipped; the outer petals free to base, the inner slightly broader; filaments pale yellow, the 3 inner, narrow, lengthening before the outer; anthers exerted up to 2 mm; style pale yellow, with stigma exerted 1–2 mm; ovary pale-orange, 3 × 1.5 mm.

Flowering occurs mainly in autumn to early winter (April to June in the southern hemisphere).