Encephalartos arenarius is a species of cycad in the family Zamiaceae. It is endemic to South Africa, where it is limited to the Eastern Cape. Its common names include Alexandria cycad and dune cycad. This species lives in densely wooded dune habitat and scrub. It is an endangered species with a maximum global population estimated at around 1500 mature individuals. Most subpopulations occur near the town of Alexandria, Eastern Cape. The main threat to the species is overcollection.