Petrocodon parviflorus, a new species of Gesneriaceae, is a typically cave-dwelling species from the limestone region in Guangxi, China. Morphologically, this new species resembles P. lui, but can be readily distinguished by differences in corolla limb lobe shape, calyx lobe surface texture, pistil style length, and central staminode length. Molecular evidence supports its close phylogenetic relationship with P. lui despite their morphological distinctness. Based on the IUCN Red List Categories and Criteria, this species is assessed as Vulnerable (VU, D2).