This study aims to describe the effect of a principal's transformational leadership on school culture; the principal's transformational leadership on organizational commitment; the principal's transformational leadership on teacher performance; school culture on teacher performance; organizational commitment to teacher performance, principal transformational leadership on teacher performance through school culture; the principal's transformational leadership on teacher performance through organizational commitment. The population of this study was 152 teachers. The research sample was 110 people taken by proportional random sampling. The researchers collected the data using an instrument consisting of the principal's transformational leadership (46), school culture (30), and organizational commitment (15), which have been tested for validity and reliability. Teacher performance data is taken from PKG. The research data were analyzed descriptively and path analysis. The study results showed that the principal's transformational leadership affected school culture. Moreover, the principal's transformational leadership affects organizational commitment. Then, the principal's transformational leadership affects teacher performance as a school culture affects teacher performance. Furthermore, organizational commitment affects teacher performance; principal transformational leadership affects teacher performance through school culture; The principal's transformational leadership influences teacher performance through organizational commitment.