Fossil range: Late Jurassic
Aviatyrannis is a genus of tyrannosaurid dinosaur from the Kimmeridgian stage of the Late Jurassic found in Portugal. It was described by Oliver Rauhut in 2003. The name means "Jurassic grandmother tyrant". Aviatyrannis is one of the oldest tyrannosaurs ever found, the oldest being Guanlong (or, possibly, Iliosuchus).
Aviatyrannis may have been a contemporary of another ancient tyrannosaur, the American Stokesosaurus. Aviatyrannis was even originally assigned to Stokesosaurus, and the fragmentary nature of the referred material fails to fully resolve the possibility that the two taxa are synonyms.
Like other early tyrannosaurs, Aviatyrannis was rather small. The holotype (IPFUB Gui Th 1), for example, is an ilium only 90 millimeters long. The type species, Aviatyrannis jurassica, was described by Rauhut in 2003.