Allocasuarina spinosissima is a shrub of the genus Allocasuarina native to a small area in the Wheatbelt and Goldfields-Esperance regions of Western Australia. The monoecious shrub typically grows to a height of 1 to 4 metres (3.3 to 13.1 ft) and produces red-brown flowers. It is in tall heath and on sandplains and grows in sandy lateritic soils.