阔齿龙属（Diadectes）是一类已经灭绝的动物，生活在二叠纪，属两栖纲迷齿亚纲。

Diadectes (meaning crosswise-biter) is an extinct genus of large, very reptile-like amphibians that lived during the early Permian period (Cisuralian epochs, 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.