| Named By: | J. P. Hunter, R. E. Heinrich & D. B. Weishampel in 2010 |
| Time Period: | Late Cretaceous |
| Location: | USA, Montana - St. Mary River Formation |
| Size: | Unavailable |
| Diet: | Insectivore |
| Fossil(s): | Partial remains |
| Classification: | | Chordata | Mammalia | Multituberculata | Neoplagiaulacidae | |
Nidimys occultus is a multituberculate which existed in the United States during the Edmontonian faunal stage of the upper Cretaceous period, and the only species in the genus Nidimys.