The European Court of Justice (ECJ) is the highest judicial authority in the European Union for interpreting EU law. It ensures that EU legislation is applied uniformly across all member states and settles legal disputes between national governments and EU institutions. In cybersecurity, the ECJ plays a crucial role by interpreting data protection laws such as the General Data Protection Regulation (GDPR), influencing how organizations handle and secure personal data. Its rulings have significant impacts on cross-border data transfers, privacy rights, and the responsibilities of companies operating within the EU. The ECJ’s decisions shape the legal landscape for cybersecurity and data privacy across Europe.