Diarrhea-associated viruses are common causes of morbidity in humans in developing countries; however, they have seldom been studied in wild primates despite their pathogenic and zoonotic potential. This is of particular concern in Madagascar, one of the world’s poorest and most biodiverse countries. To improve our understanding of diarrhea-associated viruses in human and nonhuman wild primates in Madagascar, we noninvasively collected fecal samples from 7 of the 12 lemur species of Ranomafana National Park, Madagascar and concurrently sampled humans living in proximity to the lemurs. We used standard molecular techniques to screen 84 lemur and 107 human samples for viral groups commonly associated with diarrheal disease in human populations: adenovirus, enterovirus, rotavirus, and norovirus (genogroups GI and GII). Of the seven lemur taxa examined, all were positive for one or more viral group and humans were positive for all viral groups. Norovirus GII was the most common, found in 27 % of lemurs and 37 % of humans, followed by adenovirus, found in 25 % of lemurs and 35 % of humans. The high prevalence (30–50 %) of most viral groups in mouse lemurs (Microcebus rufus) highlights their potential to serve as sentinals of pathogen spillover from humans to wild lemur populations. These results improve our understanding of the diversity and prevalence of key viral taxa in lemur and associated human populations. Further characterization of these viral group sequences has the potential to reveal novel viruses in lemurs and humans in Madagascar and would be needed to determine the zoonotic potential of the viruses detected.