The Global Minimum Tax (GMT), introduced under the OECD’s Pillar Two framework, sets a 15% minimum effective tax rate for large multinational companies to curb profit shifting and harmful tax competition. This tax reform significantly influences international accounting practices. This study looks at how the GMT impacts financial reporting systems, deferred tax accounting, effective tax rate calculations, transfer pricing documentation, compliance efforts, and corporate governance structures. Through qualitative analysis of international accounting standards and global tax policy developments from 2020 to 2026, the research assesses the adjustments multinational firms need to make. The findings reveal that GMT implementation adds complexity to accounting, increases disclosure requirements, and shifts accounting functions from basic compliance to strategic tax governance. The study concludes that updating accounting systems, improving internal controls, and integrating tax planning with financial reporting are essential for effectively responding to the changing global tax landscape.