A new lithophytic species of Gesneriaceae, Petrocodon rubrostriatus K.Tan, X.Q.Song & M.X.Ren, sp. nov. from Lvchun County, South Yunnan, China, is described and illustrated here. It closest resembles P. mollifolius (W.T.Wang) A.Weber & Mich.Möller, but the new species is differentiated from it by red to brownish-red stripes in the yellow corolla throat and 4.5 mm long bract lobes, a ca. 10 mm long style, and staminodes inserted at 2.5–3 mm from the corolla base. The species is preliminarily assessed as ‘Critically Endangered’ (CR) according to IUCN criteria, since currently only one single locality is known with a few subpopulations on a fragmented limestone cliff, with fewer than 300 individuals.