The Goods and Services Tax (GST), implemented in India on 1 July 2017, marked a landmark shift in the nation’s fiscal architecture by replacing a fragmented indirect tax regime with a unified, destination-based, value-added system. Conceived as a “one nation, one tax” initiative, GST has enhanced tax buoyancy, expanded formalisation, and curtailed the cascading effects of multiple levies. However, the reform has also exposed structural and operational challenges—ranging from complex multi-slab rates and frequent policy amendments to compliance burdens, technology bottlenecks, and centre–state revenue-sharing frictions. This paper critically examines the key issues in GST’s design and implementation, reviews contemporary literature and policy debates, and analyses recent reform proposals such as slab rationalisation and sector-specific exemptions under deliberation in 2025. Drawing from qualitative policy analysis, it presents targeted recommendations to simplify GST, ensure revenue sustainability, strengthen federal cooperation, and enhance its role as a growth-friendly and equitable tax regime.