Cerastes vipera, common names Sahara sand viper and Avicenna viper, is a viper species endemic to the deserts of North Africa and the Sinai Peninsula. No subspecies are currently recognized. Like all other vipers, it is venomous.

Adults average 20–35 cm (8–14 in) in total length (body + tail), with a maximum total length of 50 cm (1.6 ft). Females are larger than males. Small and stout, it has a broad, triangular head with small eyes set well forward and situated on the junction of the side and the top of the head.

Their hunting strategy is unique when compared to that of other viperids because they use a combination of both sit-and-wait ambushing and active hunting. Active hunting is predominantly used in the months right before hibernation to increase energy intake before the long dormant period. They are known for burying themselves in the sand to stay cool, or to ambush prey. When they are threatened, they coil up into a distinctive c-shape, causing their scales to rub together to produce a rasping or crackling sound.

Common names include Sahara sand viper, Avicenna viper, common sand viper, Egyptian asp, Cleopatra's asp, sand viper, Avicenna's sand viper, and lesser cerastes.

In arid North Africa, it is found in Mauritania, Morocco, Algeria, Mali, Tunisia, Libya, Niger, Chad, Sudan, and Egypt. In the Sinai Peninsula, it is found in Egypt, and Israel.

The type locality given is "Ægypto" (Egypt).