schools participating in a large-scale school improvement program—the Quality School Improvement Project—in Hong Kong. Using cluster analysis, schools were successfully classified into “high”, “medium”, and “low” school’s capacity in terms of principal leadership, school culture, teacher empowerment, and (perceived) students’ attitudes to learning. Subsequent analyses provided additional support for the validity of the classification and the results converged to demonstrate that schools with different capacity had differentiated improvement agenda and needs for external support. Implications for school improvement and educational reform in the Hong Kong school context were discussed