The vascular flora of Butler County, Alabama, was surveyed from 1985 to 2019. A total of 1,524 species, hybrids, or subspecific taxa in 654 genera from 170 families are reported. Fifty-seven species represented by herbarium specimens from Butler County were not re-collected during this study. The Inventory List of Rare, Threatened and Endangered Plants, Animals and Natural Communities of Alabama as compiled by the Alabama Natural Heritage Program contains 36 of the species collected. Approximately 20% of the flora (310 species), are considered non-indigenous. Families with the largest number of species, hybrids, or subspecific taxa were Asteraceae (205), Poaceae (179), Fabaceae (103), Cyperaceae (92), Rosaceae (53) and Lamiaceae (36).