India has established a rich tapestry of petroleum systems across 26 sedimentary basins throughout its exploration history. The escalating global demand for oil and gas necessitates intensified exploration efforts to identify and develop new hydrocarbon resources within potential sedimentary basins. This study aims to expand upon existing petroleum system models by conducting a comprehensive analysis of available data to identify potential yet underexplored hydrocarbon accumulations. Through comprehensive stratigraphic analyses, the presence and characteristics of critical petroleum system elements, such as organic-rich source rocks, reservoir rocks with adequate porosity and permeability, effective seal, and appropriate structures, are systematically evaluated within the unexplored basins. Particular emphasis is placed on India’s under-explored category III sedimentary basins, with the objective of conducting a detailed evaluation of their hydrocarbon potential and analysing the presence of petroleum system elements for future exploration and development opportunities. With over 20 basins classified under category III, each displays indications of key petroleum system elements, underscoring the need for further research and detailed analysis. Among these, the Himalayan Intermontane Basins, characterized by diverse tectono-sedimentary environments, display significant potential for both conventional and unconventional hydrocarbons, especially in regions such as Spiti-Zanskar, Karewa, and the Ganga Basin. Similarly, major Proterozoic basins like Vindhyan, Chhattisgarh, and Cuddapah show indications of essential petroleum system elements, warranting further evaluation. India’s Mesozoic basins, such as the Kerala-Konkan, hold potential yet lack confirmed commercial discoveries, highlighting the need for more exploration efforts. Organic-rich shale in established basins, such as Cambay, Krishna-Godavari, and Cauvery, offer substantial prospects for shale oil and gas. Additionally, coal bed methane opportunities in Gondwana basins like Damodar, Satpura, South Rewa, and Pranhita-Godavari are promising, while gas hydrate exploration in Krishna-Godavari and Andaman offshore areas requires further research. Optimizing output from established basins necessitates the exploration of untapped and unconventional resources using advanced techniques.