Plants with stems 50-100 cm tall, bearing 24 or more leaves on the upper half. Leaves spreading to recurved, 60-80 cm long and 13-15 cm wide, and deeply furrowed on the upper surface. They are shiny green in color with a pink horny margin and red-brown teeth 5-6 mm long and about 20 mm apart. Inflorescences about 100 cm long with both primary and secondary branches terminating in conical racemes up to 8 cm long bearing flowers on 10-15 mm long pedicels subtended by bracts about 5 mm long and 2-3 mm wide. Flowers red or yellow, hanging down; perianth 28-30 mm long and 8 mm wide across the ovary; anthers exceeding the perianth by about 3 mm; stigmas exserted by about 4 mm.
Aloe megalacantha grows in open, often degraded Acacia-Commiphora bushland on limestone or sand. It is becoming more common because of its ability to grow in such habitats. It is native to Somaliland (regions N1 and N2 in the Flora of Somalia) and Ethiopia.