Autonomy is a crucial factor affecting the overall functioning of educational institutions, particularly in decision-making. In developing countries, schools have faced challenges in adopting autonomy; however, it is very useful for quality education. Cambodian schools also face challenges in achieving effective autonomy across key areas. Organizational and staff autonomy is restricted by limited local governance and hiring flexibility, while financial autonomy is hindered by insufficient funding and financial management skills. Academic autonomy is constrained by centralized curriculum requirements, limiting innovative, locally-responsive teaching approaches. This study investigates the extent of school management autonomy in New Generation Schools (NGS) in Cambodia and its impact on teaching quality. The research used a mixed-methods research design; data were collected from 235 secondary school teachers across four NGSs, representing both urban and rural settings, to capture diverse perspectives. A structured questionnaire was used to measure teachers' perceptions of autonomy across key dimensions and in-depth interviews with school principals. The results indicate that the NGS enjoys a high degree of autonomy, with the respondents rating organizational, financial, staff, and academic autonomy highly. This level of autonomy enables schools to implement management practices and educational programs tailored to their specific needs, thereby enhancing teaching quality. The findings suggest sustaining and furthering these autonomies can significantly improve academic outcomes. The study concludes that extending the NGS autonomy model to more schools could enhance educational outcomes nationwide.