Guichenotia macrantha, commonly known as large-flowered guichenotia, is a shrub in the family Malvaceae. It is endemic to Western Australia. Plants grow to between 0.2 and 1.5 metres high, and produce blue-purple or pink flowers from May to September in the species native range. The species was formally described in 1846 by Russian botanist Nikolai Turczaninow.