Phrynocephalus mystaceus, also known as the secret toadhead agama and toad-headed agama, is a species of agamid lizard. It is found in southern Russia, Kazakhstan, and northwestern China (Xinjiang) and southward to northern Iran, Afghanistan, Turkmenistan, Tajikistan, Kyrgyzstan, and Uzbekistan.
Two subspecies are recognized:
Phrynocephalus mystaceus is generally associated with unvegetated tops of large, high sand dunes and occurs at elevations of -45m–1000mm (-148feet–3,000feetm) above sea level.