Ricinocarpos muricatus is a species of flowering plant in the family Euphorbiaceae and is endemic to the south-west of Western Australia.

Ricinocarpos muricatus is an erect to spreading, sticky, monoecious shrub that typically grows to height of up to 2.5 m (8 ft 2 in), its young branchlets soon glabrous.

Flowering has been observed from April to November, and the fruit is a more or less spherical or oval capsule 5–7 mm (0.20–0.28 in) long and wide.

[4] The specific epithet (muricatus) means "rough, with short, hard points", referring to the fruit.

[5] This species grows in shrubland, heath and mallee from near the Murchison River to near Esperance in the Avon Wheatbelt, Carnarvon, Coolgardie, Geraldton Sandplains, Mallee, Murchison and Yalgoo bioregions of south-western Western Australia.