| Named By: | Edward Drinker Cope in 1878 |
| Time Period: | Artinskian-Kungurian 290-272 Ma |
| Location: | USA, concentration in the Texas Red Beds |
| Size: | Between 1.5 and 3 meters long |
| Diet: | unavailable |
| Fossil(s): | Many specimens are known allowing for accurate reconstruction |
| Classification: | | Chordata | Amphibia | Reptiliomorpha | Diadectomorpha | Diadectidae | |
| Also known as: | | Nothodon | Empecocles | Helodectes | Empedias | Chilonyx | Bolbodon | Diadectoides | Animasaurus | |
Diadectes (meaning crosswise-biter) is an extinct genus of large, very reptile-like amphibians that lived during the early Permian period (Artinskian-Kungurian stages of the Cisuralian epoch, between 290 and 272 million years ago). Diadectes was one of the very first herbivorous tetrapods, and also one of the first fully terrestrial animals to attain large size.