The predominantly Australasian genus Patersonia R. Br. (Iridaceae, Patersonioideae) includes 18 species in Australia, one in New Caledonia, and just one currently recognized species in the Malesian archipelago, although two more have been described previously but are now reduced to synonymy. After examining the available collections of the genus from this vast area, I have identified two distinct sets of populations in Borneo, two more in New Guinea, one in Sumatra, and one in Mindoro, The Philippines. Many collections lack flowers or are poorly preserved, yet greater-than-expected differences in vegetative and some fruit features for a single species are evident among the six population sets. Morphological variation includes leaf size; marginal vestiture and microscopic surface structure; flowering stem orientation, width, and length relative to leaves; inflorescence spathe and floral bract vestiture; and absence or presence and type and amount of pubescence on perianth tube and ovary. Recognition of just one hypervariable Malesian species does not adequately reflect the biological situation. I propose the following: recognition of P. borneensis Stapf and the west New Guinean P. novo-guineensis Gibbs, currently subsumed in P. lowii Stapf; addition of a second species in Papua New Guinea, P. inflexa Goldblatt; and treatment of the Sumatran highland plants as P. sumatrensis Goldblatt from Indonesia. Philippine plants from Mindoro match none of these and represent another species, P. philippinensis Goldblatt. Lectotypes are designated for the two names P. lowii and P. novo-guineensis. This taxonomy awaits provenance of flowers with well-preserved perianths of all but P. lowii and P. borneensis and capsules and seeds of P. philippinensis, but are unlikely to alter this treatment. Floral differences among most Patersonia species are small, except for the vestiture on tepals and tube visible in many of the available specimens, and for the most part involve only modest differences in size and color of the tepals.