This research paper critically examines the concept, evolution, and operational framework of judicial review in two of the world’s largest democracies, India and the United States. Judicial review serves as a fundamental mechanism to uphold the supremacy of the Constitution and safeguard civil liberties by enabling the judiciary to invalidate legislative and executive actions that violate constitutional provisions. The paper explores the historical origins of judicial review, tracing its formal establishment in the U.S. through Marbury v. Madison and its evolution in India through cases like Kesavananda Bharati v. State of Kerala. A comparative approach is employed to analyze jurisprudential doctrines, such as the separation of powers, checks and balances, and proportionality, and their role in shaping judicial review. The article highlights key similarities between the two systems, including the use of precedent and the judiciary’s role in preserving democratic values. Simultaneously, it underscores major differences in judicial philosophy, such as the U.S. emphasis on originalism and textualism versus India’s more activist and expansive interpretative approach, supported by Public Interest Litigation (PIL). The study also evaluates the limitations imposed on judicial review in both countries, including constitutional constraints, political doctrines, and institutional boundaries. It ultimately argues that while the methods differ, judicial review in both jurisdictions remains an essential guardian of constitutionalism and justice. The paper concludes by advocating for a balanced and responsible exercise of judicial power to ensure the continued protection of individual rights and democratic governance in an evolving global landscape.