The establishment of the National Institution for Transforming India (NITI Aayog) in 2015 marked a major shift in India's approach to development planning. Replacing the Planning Commission, NITI Aayog was designed as a policy think tank to promote cooperative federalism, innovation, evidence-based policymaking, and sustainable development. Unlike its predecessor, it does not allocate financial resources but provides strategic policy advice and encourages collaboration among the Union Government, State Governments, experts, and other stakeholders. This study examines the role of NITI Aayog in India's transformation by analysing its institutional framework, major initiatives, and contribution to governance reforms. The study is based on secondary data collected from government reports, books, journal articles, and publications of international organizations. The findings indicate that NITI Aayog has strengthened policy coordination, promoted innovation, encouraged data-driven governance, and improved Centre–State cooperation through initiatives such as the Aspirational Districts Programme, Atal Innovation Mission, and SDG India Index. However, its advisory nature and dependence on implementation by ministries and state governments continue to limit its overall effectiveness. The paper concludes that NITI Aayog has become an important institution for promoting inclusive, innovative, and sustainable development in India. Its future success will depend on stronger institutional coordination, effective implementation, and continued collaboration among all stakeholders.