Vespertilio is a genus of bats in the family Vespertilionidae.

The common name for this family is vesper bats, which is a better-known classification than Vespertilio.

[citation needed] Species within the genus Vespertilio are: Vespertilio is the oldest accepted genus name for bats.

When Vespertilio was described in 1758, it was equivalent to the modern taxonomic order, encompassing all of Chiroptera (all bats), which Carl Linnaeus grouped with the primates due to certain characteristics mentioned by Linnaeus that bats seemed to share with actual primates.

[1] Variably, until 1779, Vespertilio was considered either the only chiropteran genus, or one of two, including Pteropus.