Global environmental degradation and climate change have reshaped the fiscal policy agenda, requiring governments to integrate ecological priorities into public finance. This study examines green budgeting as a strategic fiscal governance instrument that aligns budgetary decisions with environmental sustainability and the Sustainable Development Goals (SDGs). Drawing on theoretical frameworks from environmental economics, public choice, and institutional economics, the paper explores the conceptual foundations, methodological approaches, and institutional dynamics of green budgeting. International experiences—including those of the European Union, France, Ireland, New Zealand, Indonesia, and the Philippines—are analyzed to identify best practices and persistent challenges. The findings highlight that green budgeting enhances fiscal transparency, accountability, and resource efficiency while supporting low-carbon innovation and climate-resilient growth. However, methodological complexities, data limitations, and political-institutional constraints remain major barriers to its full implementation. The study argues that integrating climate objectives into budget cycles not only strengthens fiscal discipline but also provides a financial architecture for sustainable development. Ultimately, green budgeting is presented as a transformative approach that redefines the role of public finance in the transition toward a more sustainable global economy.