Elmidae, commonly known as riffle beetles, is a family of beetles in the superfamily Byrrhoidea described by John Curtis in 1830.

Both adults and larvae are usually aquatic, living under rocks in fast-flowing shallow areas of streams, such as riffles, feeding on algae and biofilms.

[1] There are more than 150 genera and 1,500 described species in Elmidae.

[2][3][4][5] The oldest record of the group is Cretohypsilara from the Cenomanian aged Burmese amber.

This Elateriformia-related article is a stub.