Pediomys is an extinct genus of pediomyid marsupial from the Late Cretaceous of North America.

Pediomyinae was then expanded by the work of Clemmens in the 1960s, who elevated the subfamily to Pediomyidae and described the new species P. cooki, P. krejcii, and P. florencae, all from the Lance Formation.

The new pediomyid species P. exiguus, P. clemensi, P. prokrejcii and the genus Aquiladelphis were then named by Fox and Sahni in the 1970s, with P. clemensi and P. prokrejcii from the Campanian Judith River Formation and suggested to be ancestral to P. cooki and P. krejcii respectively.

[1] Pediomyidae and Pediomys expanded to include such a diversity of species and genera that it began to be suspected to be an artificial group.

For P. exiguus, which was found to not be a member of Pediomyidae, Davis named the new genus Apistodon in reference to its unstrustworthy classification.