Paraboea gracillima Kiew (Gesneriaceae) is described from Perlis, Malaysia, and from Ban Khamphaengphen in Peninsular Thailand. Paraboea lambokensis Kiew is described from two hills in Kelantan, Malaysia. Both are restricted to limestone. Paraboea lambokensis is endemic in Peninsular Malaysia and is Critically Endangered, while P. gracillima, which is protected in the Perlis State Park, is categorised as Least Concern.

The genus Paraboea Ridl. (Gesneriaceae) is revised. It is found in Bangladesh, Bhutan, Burma, Cambodia, southern China, India (Assam), Indonesia (Sumatra, Java, Borneo, Sulawesi), Laos, Malaysia (Peninsular and Borneo), Philippines, Thailand and Vietnam, mostly from limestone habitats. Eighty-nine species and five varieties are recognised. Four new species and one new variety are described: Paraboea apiensis Z.R.Xu, Paraboea argentea Z.R.Xu, Paraboea graniticola Z.R.Xu, Paraboea paraprimuloides Z.R.Xu and Paraboea harroviana var. ovata Z.R.Xu. In addition two taxa are highlighted as possible new species but are not described here due to insufficient material. The treatment includes one new combination for a species, Paraboea harroviana (Craib) Z.R.Xu, one new combination for a variety, Paraboea schefferi var. ambigua (C.B.Clarke) Z.R.Xu, one new status for a variety, Paraboea rufescens var. tomentosa (Barnett) Z.R.Xu, and one new name, Paraboea primuloides Z.R.Xu. Fifty-one line drawings are included. A key is presented and all taxa are described. Preliminary conservation assessments are given.