Taddei's serotine (Eptesicus taddeii) is a species of medium-sized bat belonging to the family Vespertilionidae. It is restricted to the Atlantic Forest of southern Brazil.
The bat has a total length of up to and is most similar to Eptesicus brasiliensis but can be distinguished from that species by its more robust appearance, redder colouring, larger muzzle and rounder-shaped ears. The specific name honours the Brazilian zoologist Valdir Antônio Taddei.