Jacksonia horrida is a species of flowering plant in the family Fabaceae and is endemic to the south-west of Western Australia. It is an erect or spreading to prostrate, bushy shrub with greyish-green branches ending in short, flattened, sharply-pointed side branches, the leaves reduced to scales and the flowers scattered and yellow-orange with red markings.
Jacksonia horrida is an erect or spreading to prostrate, bushy shrub that typically grows up to high and wide. The branches are greyish-green, ending in short, flattened, sharply-pointed side branches long and wide. The penultimate branches are densely hairy. The leaves are reduced to broadly egg-shaped scale-leaves long and wide. The flowers are scattered on the branches with scale leaves at the base on a pedicel long, with egg-shaped bracteoles that fall off as the flowers open. The floral tube is long and the sepals are membranous, long and wide. The standard petal is yellow-orange with red markings, long and deep, the wings yellow-orange with red markings, long and deep, and the keel is red, long. The stamens have pink filaments long. Flowering occurs from throughout the year, and the fruit is a woody, densely hairy pod long and wide.
Jacksonia horrida was first formally described in 1825 by Augustin Pyramus de Candolle in his Prodromus Systematis Naturalis Regni Vegetabilis. The specific epithet (horrida) means 'prickly' or 'very rough'.
This species of Jacksonia grows in shrubland or woodland, often in winter-wet areas or on coastal dunes, between Lake Clifton and West Cape Howe in the Esperance Plains, Jarrah Forest, Swan Coastal Plain and Warren bioregion of south-western Western Australia.