Acacia insolita is a shrub belonging to the genus Acacia and the subgenus Phyllodineae that is endemic to south western Australia.
The shrub typically grows to a height of 0.1to and has glabrous or hairy stems and foliage. The stems have long stipules. The leaves have a bipinnate form and are usually persistent on mature plants. Each pinnae normally contain one pair with 2 to 12 pinnules. Each green pinnule has a lanceolate to narrowly oblong or elliptic shape and a length of and a width . The narrowly linear, flat or quadrangular phyllodes have a length of and a width of .[1] It produces yellow-cream flowers from June to September. The simple inflorescences occur singly in the axils. The spherical flower-heads contain 12 to 19 cream to golden coloured flowers. After flowering linear to narrowly oblong seed pods form with a length of around and a width of . the glossy black to dark brown seeds within the pods are around in length.[1]
There are three recognised subspecies:
It is native to an area in the South West region of Western Australia where it is found on hills and ridges growing in gravelly sandy soils often containing laterite. The plant along the Darling Range from around Marradong in the north to Nannup in the south.[1]