| Named By: | A. Arcucci & C. A. Mariscano in 1998 |
| Time Period: | Middle Triassic, Anisian-Ladinian |
| Location: | Argentina, La Rioja Province - Chanares Formation |
| Size: | Unavailable |
| Diet: | Carnivore |
| Fossil(s): | Partial remains of armour, post cranial skeleton and skull |
| Classification: | | Chordata | Reptilia | Archosauriformes | Doswelliidae | |
Tarjadia is an extinct genus of Triassic archosauriform. It is known from a single species, T. ruthae, first described in 1998 from the Middle Triassic Los Chanares Formation in Argentina. Partial remains have been found from deposits that are Anisian-Ladinian in age. The genus is known mostly from osteoderms, as well as several vertebrae and fragments of the skull. Tarjadia predates the Late Triassic aetosaurs and phytosaurs, two early groups of crurotarsans with heavy plating, making it one of the first heavily armored archosaurs. However, its classification within Archosauria is uncertain, as the known remains are fragmentary.