Viviparus, commonly known as the river snails, is a genus of large, freshwater snails with an operculum, aquatic gastropod molluscs.

They are primitive members of the clade Caenogastropoda. The old name of the genus was Paludina.

This genus is palaearctic in distribution, and is known from the Jurassic to the Recent.

Viviparus belongs to the subfamily Viviparinae. Its taxonomy is currently under development and many of its species are often included in other related genera. It includes the following species: