The purpose of this study was to determine and analyze the effect of transformational leadership style and motivation on teacher performance mediated by organizational commitment. The population in this study were all Madrasah aliyah teachers in Yogyakarta Municipality. The sample selection was 117 respondents. The sampling technique used was purposive sampling technique. The instrument used in this research was a questionnaire. The type of research used was quantitative research and the type of data was primary data that was sourced directly from the questionnaire distribution survey. The research model was analyzed using Structural Equation Modeling (SEM) with the help of AMOS Software. The results of this study indicated that (1) Achievement motivation had a positive and significant effect on teacher performance. (2) Transformational Leadership had a positive and significant effect on teacher performance. (3) Achievement motivation had a positive and significant effect on organizational commitment. (4) Transformational Leadership had a positive and significant effect on organizational commitment. (5) Organizational commitment had a positive and significant effect on teacher performance. (6) Achievement motivation had a positive and significant effect on teacher performance through organizational commitment. (7) Transformational Leadership had a positive and significant effect on teacher performance through organizational commitment.