Clyomys is a South American rodent genus in the family Echimyidae. It contains two species, found in tropical savannas and grasslands from circa 100 m (300 ft) to 1,100 m (3,600 ft) elevation in central Brazil and eastern Paraguay.

The term Clyomys derives from the two ancient greek words κλύω (klúō, or clyo), meaning "to listen, to prick up one's ears", and μῦς (mûs), meaning "mouse, rat".

The Clyomys species are as follows:

• Broad-headed spiny rat (Clyomys laticeps)
• † Clyomys riograndensis

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