Bureaucratic reform is a strategic agenda of national development aimed at creating clean, accountable, and quality governance. The development of Integrity Zones (ZI) is a concrete instrument for accelerating bureaucratic reform at the work unit level, culminating in the awarding of Corruption-Free Work Unit (WBK) and Clean and Serving Bureaucracy (WBBM) designations. This study aims to analyze the essence, mechanisms, challenges, and best practices of ZI development through the regulatory framework of PermenPANRB No. 90 of 2021 and the perspective of good governance. The method used is normative legal research with a statute approach and case study approach. The results indicate that ZI development encompasses three main dimensions of integrity: anti-corruption, performance, and public service, operationalized through six areas of bureaucratic reform. Achieving WBK/WBBM status requires valid and comprehensive documentation, impactful innovation, and positive public validation. This study recommends strengthening the internalization of ZI values, improving APIP capacity, and ensuring implementation sustainability after obtaining the designation