The Mount Oku hylomyscus is a rare mouse known only from the slopes of Mount Oku in Cameroon. A survey on the mountain collected seven specimens.
It is described as larger than other Hylomyscus species. Five measured specimens had head-and-body lengths of 89–112 mm and tails of 129–154 mm.
Researchers collected seven specimens from the slopes of Mount Oku. The paper describes the species as rare and places the survey in the mountain forest.
An extinction-risk assessment has not been added yet.