Acacia chapmanii is a shrub of the genus Acacia and the subgenus Plurinerves that is endemic to south western Australia.
The shrub typically grows to a height of 0.3to and has a dense and intricate habit. It has glabrous with persistent and spinose stipules with a length of . Like most species of Acacia it has phyllodes rather than true leaves. The evergreen, sessile phyllodes that are usually continuous with the branchlets have a length of and a diameter of . The rigid, glabrous and pungent phyllodes have a total of eight distant and raised nerves with three nerves on each face when flat. It blooms from August to September and produces yellow flowers.
There are two recognised subspecies:
It is native to an area in the Wheatbelt region of Western Australia where it is commonly situated on plains, along the margins of swamps, in depressions and in and around saline flats growing in sandy, clay or loamy soils often containing gravel and over and around laterite. It has adisjunct distribution with populations near Three Springs in the north and around Bolgart in the south where it is often part of heath or scrub communities.[1]