This study investigates the quality of Inclusive education implementation at Private School X, an International school in Indonesia committed to a zero-reject policy for students with special needs. Framed by Universal Design for Learning (UDL), Total Quality Management (TQM), and inclusive education theory, the research explores how inclusive practices are realized amidst challenges such as limited teacher preparedness, inadequate resources, and the absence of clear institutional policies. Using a qualitative case study approach involving interviews, focus groups, and document analysis, the study identifies key strategies that support inclusion, such as differentiated instructions, flexible assessments, and school-initiated professional development. Findings reveal that while efforts to personalize learning and foster accessibility are evident, systematic gaps in leadership coordination, policy clarity, and resource allocation hinder the sustainability of high-quality inclusion. The research underscores that the true quality of inclusive education lies not only in student participation but in the institution’s ability to integrate equity, flexibility, and support across all levels. Recommendations are provided to enhance teacher training, policy implementation, and inclusive leadership, contributing a practical framework for improving inclusive education in similar contexts.