We investigated the taxonomic status of the Indian forms of the Dendrelaphis pictus (Gmelin, 1789) group on the basis of multivariate analyses of morphological data taken from 176 museum specimens and two living specimens. A geographically isolated form from the Western Ghats, southwest India, is described as a new species. The subspecies Dendrelaphis pictus andamanensis (Anderson, 1871), an endemic from the Andaman Islands, is given specific status. Finally, the population of D. pictus from Indochina and northeast India, although superficially homogeneous, is shown to be comprised of two morphologically distinct forms. These forms are distributed parapatrically with a transition near the northern and northwestern borders of Indochina. The two forms are considered to represent distinct evolutionary lineages. The name Dendrelaphis proarchos (Wall, 1909) is revalidated to represent the northwestern form. The southeastern form is referred to as D. pictus (Gmelin, 1789). Whether intergradation between D. pictus and D. proarchos occurs at the contact zone is not clear.