We reassess the taxonomy of the Indian endemic snake Xylophis captaini and describe a new species of Xylophis based on a type series of three specimens from the southernmost part of mainland India. Xylophis deepaki sp. nov. is most similar phenotypically to X. captaini, with which it was previously confused. The new species differs from X. captaini by having a broader, more regular and ventrally extensive off-white collar, more ventral scales (117–125 versus 102–113), and by lack of flounces on the body and proximal lobes of the hemipenis. Phylogenetic analysis of mitochondrial 16S DNA sequences strongly indicates that the new species is most closely related to X. captaini, differing from it by an uncorrected pairwise genetic distance of 4.2%. A revised key to the species of Xylophis is provided.