Swainsona thompsoniana is a species of flowering plant in the family Fabaceae and is endemic to inland northern Western Australia.

It is a prostrate annual herb, with imparipinnate leaves with 3 to 6 pairs of narrowly egg-shaped to egg-shaped leaflets with the narrower end towards the base, and racemes of up to 3 mauve and cream-coloured to yellow flowers.

[2][4] The specific epithet (thompsoniana) honours Joy Thompson "in recognition of her contribution to the taxonomy of Swainsona".

[2] This species of pea grows on open flood plains between Pannawonica, Mount Florence Station, Tom Price and Wittenoom in the inland of northern Western Australia.

[2][3] Swainsona thompsoniana is listed as "Priority Three" by the Government of Western Australia Department of Biodiversity, Conservation and Attractions,[3] meaning that it is poorly known and known from only a few locations but is not under imminent threat.