Hibbertia trichocalyx is a species of flowering plant in the family Dilleniaceae and is endemic to the south coast of Western Australia.

It is an erect, spreading shrub with oblong to elliptic leaves and yellow flowers with eleven stamens arranged around three glabrous carpels.

Hibbertia trichocalyx is an erect, spreading shrub that typically grows to a height of up to 60 cm (24 in) and has densely, softly-hairy branchlets.

The flowers are arranged singly in leaf axils or on the ends of short side-branches and are sessile with two or three cream-coloured to pale brown bracts 2.5–5 mm (0.098–0.197 in) long.

The five petals are yellow, egg-shaped with the narrower end towards the base and 4–7 mm (0.16–0.28 in) long with a notch at the tip.