Nocturnal aculeate wasps (Hymenoptera: Chyphotidae, Brachycistidinae [Tiphiidae], and Mutillidae) are abundant in North America's deserts, yet their patterns of diversity are not well studied. Here we report on the diversity of these groups in Joshua Tree National Park (JTNP). On the basis of collection data from a transect of 14 sampling sites transitioning from the Mojave to the Sonoran Desert, our study shows that there are at least 11 species of Chyphotes (Chyphotidae), based on the collection of 1,513 specimens, there are at least 22 species of brachycistidine Tiphiidae species in five genera, based on the collection of 13,960 specimens, and at least 35 species of nocturnal mutillids in six genera, based on 8,477 specimens. Brachycistidine Tiphiidae populations peak earlier in the season compared with the other two groups. Also we found an increase in Chyphotidae, Brachycistidinae, and Mutillidae diversity and abundance with decreasing latitude. Several species appear to be spatially restricted to one desert region; others exhibit temporal isolation, only being collected during specific months. Our study suggests that JTNP houses a diverse community of nocturnal aculeate wasps with the Sonoran Desert being more diverse than the Mojave Desert.