Acacia acrionastes is a shrub belonging to the genus Acacia and the subgenus Phyllodineae that is native to parts of eastern Australia. The shrub or tree has a spindly habit and typically grows to a height of 1.5 to 8 m (4 ft 11 in to 26 ft 3 in) and has smooth bark. It has linear phyllodes that are straight to slightly curved with a length of 6 to 17 cm (2.4 to 6.7 in) and a width of 2 to 4 mm (0.079 to 0.157 in). It blooms between July and August and produces inflorescences with creamy yellow flowers.