Acacia nigricans is a species of wattle which is endemic to an area on the south coast of Western Australia. It is a shrub which ranges from 0.4 to 2 metres in height. It produces yellow, globular flowers between mid-winter and late spring. The species was formally described in 1807 by French naturalist Jacques Labillardière who gave it the name Mimosa nigricans, based on plant material collected from Esperance. It was transferred to the genus Acacia in 1813 by botanist Robert Brown.