Micromomys fremdi was named by Fox (1984). Its type specimen is UA 21010, a mandible (incomplete left dentary having c?, p2-4, m1-3, and alveolus for i1), and it is a 3D body fossil. Its type locality is Saxonella Locality, which is in a Ti3 lacustrine siltstone/shale in the Paskapoo Formation of Canada. It is the type species of Foxomomys.

It was recombined as Foxomomys fremdi by Chester and Bloch (2013).