A new species of Melastomataceae, Sonerila longipedunculata Resmi & Nampy sp. nov., is described from the southern Western Ghats, India. It is morphologically close to S. travancorica, but differs by the tuberous root stock, fleshy stems, ovate to cordate lamina, longer, angular peduncles, 3-ribbed hypanthium, ovate-elliptic petals, acute anthers, and 3-ribbed capsules. Detailed description, distribution map, and photographic images are provided. The morphological differences with relevant species are discussed. The status of the new species is provisionally assessed here as ‘critically endangered’ according to IUCN Red List Categories and Criteria. The name Sonerila travancorica is lectotypified and its identity is discussed. The status of Sonerila longipetiolata is discussed and is synonymised under S. travancorica.