Public Financial Management (PFM) plays a critical role in ensuring fiscal discipline, transparency, accountability, and effective service delivery within subnational governments. This review paper comparatively examines the efficiency of PFM systems in subnational governments in the United States and Ghana, with particular emphasis on budgeting processes, revenue mobilization, expenditure control, fiscal decentralization, public accountability, digital financial systems, and institutional governance frameworks. The study explores how differing political structures, administrative capacities, and economic conditions influence the performance and efficiency of state and local governments in managing public resources. Drawing on existing empirical studies, policy reports, and institutional frameworks, the review identifies key strengths in the United States’ decentralized fiscal governance model, including advanced financial reporting standards, performance-based budgeting, and robust audit mechanisms, while also highlighting challenges such as pension liabilities, intergovernmental fiscal imbalances, and political polarization. In contrast, Ghana’s subnational PFM system demonstrates ongoing reforms aimed at strengthening fiscal decentralization, transparency, and accountability through initiatives such as the Ghana Integrated Financial Management Information System (GIFMIS) and local government capacity-building programs, although persistent challenges remain in revenue generation, corruption control, weak institutional enforcement, and limited technical expertise. The paper further analyzes comparative lessons, reform strategies, and best practices that can enhance efficiency, fiscal sustainability, and public trust in subnational governance systems across developing and developed economies. The study concludes that effective PFM efficiency at the subnational level depends on strong institutional capacity, transparent fiscal governance, technological integration, citizen participation, and consistent policy implementation.