Thomasia triphylla is a small shrub that is endemic to the south-west of Western Australia.

The calyx are purple, pink or white, smooth, five free stamens and filaments 4 mm (0.16 in) long.

[2] Thomasia triphylla was first formally described in 1821 by Jacques Etienne Gay and the description was published in Memoires du Museum d'Histoire Naturelle.

[3][4] The specific epithet (triphylla) refers to "the 2 stipules at the base of the petiole are large and leaf like".

[5] This species grows in limestone and sand dunes in coastal areas of south-west Western Australia and several locations from Albany to Esperance.