This study aimed to develop a conceptual model of the role of differentiation strategy and organizational citizenship behavior in mediating the effect of transformational leadership on the performance of private high schools in Pekanbaru. The sample was 140 principals and vice-principals of private high schools in Pekanbaru. The data obtained were processed using Structural Equation Modeling Partial Least Square (SEM PLS). The findings in this study are that transformational leadership has a positive effect on the performance of private high schools in Pekanbaru, differentiation strategy and organizational citizenship behavior mediate the effect of transformational leadership on the performance of private high schools in Pekanbaru. The most effective pathway to affect the performance of private high schools is the mediating pathway of organizational citizenship behavior on the effect of transformational leadership on the performance of private high schools.