T This study aims to evaluate the implementation of the core tax in enhancing taxpayer compliance. the primary focus is to analyze stakeholder perceptions regarding system effectiveness and efficiency, the impact of automation features on compliance behavior, and to formulate improvement strategies during the transition period. using a qualitative approach with thematic analysis, data were gathered through in-depth interviews with three strategic stakeholder groups: tax consultants, corporate tax divisions, and directorate general of taxes (dgt) officials. the results indicate that while coretax is deemed successful in terms of efficiency specifically in reducing administrative burdens and accelerating business processes stakeholder perceptions regarding its effectiveness remain negative due to suboptimal system readiness, service quality, and feature performance. in terms of behavior, coretax has successfully driven a transition toward digital-based voluntary compliance, facilitated by ease of access and data integration. however, despite a highly positive attitude from users, the main transition barriers stem from technical system constraints and insufficient human resource training. this study concludes that mitigation strategies must prioritize it infrastructure stability and comprehensive training to convert user intent into actual compliance behavior and ensure long-term system sustainability.