How biodiversity is generated and maintained is a fundamental question in ecology and evolutionary biology, and studying diversification can give us key insights into this process. In my thesis, I carried out species delimitation and investigated the pattern of lineage and morphological diversification in a continental radiation of Hemidactylus geckos. The underlying role of climate in generating these patterns was also examined. Through systematic sampling and molecular phylogenetic work, evolutionary history of these geckos was traced. Fossil-calibrated phylogeny showed that Hemidactylus started diversifying ~36Mya, with an early-burst in lineage diversification. Using a hypothesis testing framework, I show that the drying caused during the Eocene-Oligocene cooling could have provided ecological opportunity driving lineage diversification. I then examined ecological diversification by studying morphological evolution. Species of Hemidactylus are found in various microhabitats and the relationship between habitat specialists and their morphology was assessed. We found significant differences in morphology between terrestrial and climbing species. Unlike lineage diversification, morphological diversification showed a delayed increase in disparity. Ancestral state reconstruction of terrestrial and climbing forms showed that the terrestrial geckos have evolved at least five times independently across the phylogeny. The shift from climbing to terrestrial state began after 15Mya, concurrent with aridification in Peninsular India that led to the establishment of open habitats. Thus, this study highlights the role of two disparate climatic events governing the asynchronous lineage and morphological diversification in this adaptive radiation.