American brown bat may refer to several species of vesper bats native to the Americas:
Big brown bat (Eptesicus fuscus), a larger species widely distributed across North America, Central America, and northern South America. Little brown bat (Myotis lucifugus), a smaller species common throughout North America.
See also
Brown bat (disambiguation) Eptesicus — genus containing many species commonly called serotines or brown bats.