The rapid growth of cryptocurrency markets has created significant regulatory challenges for governments, financial authorities, and policymakers worldwide. This study examined how regulatory fragmentation affected financial stability, investor protection, and monetary policy effectiveness across different economies. A qualitative library research approach was employed by reviewing academic literature, international policy reports, and regulatory documents concerning cryptocurrency governance. The findings revealed that differences in regulatory frameworks across jurisdictions created governance gaps, facilitated regulatory arbitrage, complicated cross-border supervision, and weakened risk management. Regulatory fragmentation also increased vulnerabilities to financial instability, limited the effectiveness of investor protection mechanisms, and created challenges for monetary policy implementation in increasingly digitalized financial systems. These challenges were interconnected and could not be effectively addressed through isolated national measures. The study concluded that stronger international regulatory coordination and greater consistency in cryptocurrency governance are essential to strengthen market integrity, financial resilience, investor confidence, and long-term monetary stability in the evolving global digital economy.