Thysanotus sabulosus is a species of flowering plant in the Asparagaceae family, and is endemic to the south-west of Western Australia. It is a perennial herb with a cylindrical rootstock, fibrous roots, about twelve perennial leaves and umbels of up to three flowers with narrowly elliptic sepals, egg-shaped, fringed petals and six stamens of differing lengths.
Thysanotus sabulosus is a perennial herb with a cylindrical rootstock about in diameter, fibrous roots, and about twelve apparently perennial leaves, the innermost leaves long and the outermost leaves almost bract-like. The flowers are borne in panicles about long with umbels of up to three flowers, each on a pedicel long. The perianth segments are long, the sepals narrowly elliptic, about wide, and the petals egg-shaped, about wide, with a fringe long. There are six stamens, the three outer anthers long and the inner anthers long. The style is long. Flowering occurs from October to December, and the seeds are more or less cylindrical, about long and in diameter, with a stalked, yellow to orange aril.
Thysanotus sabulosus was first formally described in 1972 by Norman Henry Brittan in the Journal of the Royal Society of Western Australia from specimens he collected west of Newdegate on the Newdegate-Lake Grace road in 1960. The specific epithet (sabulosus) means 'growing in sandy places'.
This species of Thysanotus grows in deep yellow sand and lateritic gravel on sandplains near Newdegate and Kulin, in the Avon Wheatbelt and Mallee bioregions of south-western Western Australia.
Thysanotus sabulosus is listed as "Priority One" by the Western Australian Government Department of Biodiversity, Conservation and Attractions, meaning it is known from only a few populations that are under immediate threat from known threatening processes.