Hypnomys, otherwise known as Balearic giant dormice, is an extinct genus of dormouse, from the family Gliridae. Its species are considered examples of insular gigantism. They first appear in the fossil record during the Early Pliocene, presumably due to the Messinian salinity crisis causing a connection with mainland Europe, and disappear during the Holocene after human arrival on the Balearics. They were only of only three native land mammals to the islands, alongside Nesiotites and Myotragus. A 2020 mitochondrial DNA analysis found that its closest living relative was Eliomys, from which it diverged around 13.67 million years ago. The dental morphology of the earlier species is more complex than that of Eliomys, suggesting it is derived from or a similar form, rather than an early diver