Danthonioideae is a mainly southern hemisphere subfamily of grasses, containing the single tribe Danthonieae and three unplaced genera, with altogether roughly 300 species. It includes herbaceous to partially woody perennial or annual (less common) grasses that grow in open grasslands, shrublands, and woodlands. It belongs to the PACMAD clade of grasses, but unlike some other lineages in that clade, grasses in the Danthonioideae exclusively use the C3 photosynthetic pathway. Its sister group is the subfamily Chloridoideae.