Thomasia rulingioides is a species of flowering plant in the family Malvaceae and is endemic to the south-west of Western Australia.

The sepals are pink to purple, joined for about half their length and the petals are tiny.

[2][3] Thomasia rulingioides was first formally described in 1845 by Ernst Gottlieb von Steudel in Lehmann's Plantae Preissianae from specimens collected in 1839.

[6] This thomasia grows in deep sand over limestone, in scattered locations, mainly near the coast between Perth and Geraldton but also near Esperance and further inland near Three Springs in the Geraldton Sandplains and Swan Coastal Plain bioregions of south-western Western Australia.

[2][3] Thomasia rulingioides is listed as "not threatened" by the Western Australian Government Department of Biodiversity, Conservation and Attractions.