Mahonia nanlingensis (Berberidaceae), a new species from Nanling Mountains in China, is described and illustrated. It is distinguished morphologically from allied species by its 7–9 fine-toothed leaflets, the rounded or cordate apex of the outer sepals, narrowly incised apex of petals, truncate stamen anthers and broadly discoid stigma. Phylogenetic analysis based on chloroplast and nuclear ribosomal DNA (nrDNA) sequences further supports its recognition as a new species. Due to habitat disturbance and medicinal use, M. nanlingensis is assessed as “Vulnerable” (VU) according to the IUCN Red List categories and criteria.