The golden langur is one of the most range restricted colobine monkey, confined to the region between Sunkosh and Manas rivers in Bhutan and adjoining Assam (India). It is closely related to the widely distributed capped langur which is distributed from Eastern Bhutan, Northeast India, parts of Northern Bangladesh to Southern China, and Northwestern Myanmar. Golden langur has been divided into two subspecies whereas capped langurs into four. However, the subspecies status of golden langur is still being debated. Previous studies have hypothesized that an isolated population of capped langurs might have speciated into golden langurs due to geographical barriers like rivers and mountains. This would represent a classic case of budding speciation; wherein peripheral isolates of widely distributed species evolve into a distinct lineage. Furthermore, the presence of intermediate forms between golden langurs and capped langurs found in an overlap zone in central Bhutan hints at a possible hybridization between these two species. Alternately, these intermediate forms might represent clinal variation between golden and capped langurs (intergradation). Given this background, for my thesis research, I aim to investigate the origin and evolutionary history of golden langurs vis-a-vis capped langurs by using multiple nuclear and mitochondrial markers. Genetic data will be used to address three specific questions. 1) Does genetic data support splitting of golden langur into two subspecies? 2) Is there genetic evidence for budding speciation? 3) Are the intermediate forms a case of hybridization or does it represent intergradation?