Patersonia pygmaea is a species of plant in the iris family Iridaceae and is endemic to the south-west of Western Australia.

Patersonia pygmaea is a tufted perennial herb that forms a rhizome and has woody stems 20–30 mm (0.79–1.18 in) long.

Flowering occurs from September to October and the fruit is an oval capsule 20–25 mm (0.79–0.98 in) long, containing brown seeds.

[2][3] Patersonia pygmaea was first described in 1840 by John Lindley in A Sketch of the Vegetation of the Swan River Colony.

[2][3] Patersonia pygmaea is classified as "not threatened" by the Western Australian Government Department of Biodiversity, Conservation and Attractions.