Allocasuarina thuyoides, commonly known as horned sheoak,[2] is a species of flowering plant in the family Casuarinaceae and is endemic to the south-west of Western Australia.

It is monoecious or dioecious shrub that has its leaves reduced to scales in whorls of five or six, the mature fruiting cones 8–20 mm (0.31–0.79 in) long containing winged seeds usually 5.0–6.0 mm (0.20–0.24 in) long.

[2][3] This sheoak was first formally described in 1845 by Friedrich Anton Wilhelm Miquel who gave it the name Casuarina thuyoides in Lehmann's Plantae Preissianae.

[4][5] It was reclassified in 1982 as Allocasuarina thuyoides by Lawrie Johnson in the Journal of the Adelaide Botanic Gardens.

[7] Allocasuarina thuyoides is widely distributed in the south-west of Western Australia, occurring from the Murchison River south to Albany and east to Esperance, where it grows in heath on laterite and sandplains.