This study examined the effects of principal leadership style and teacher work motivation on teacher performance, with job satisfaction as a mediating variable, in public junior high schools in Serang Regency. Research Methodology: This study used a quantitative approach with a cross-sectional survey design. Data were collected using a 5-point Likert-scale questionnaire administered to 122 teachers from six public junior high schools in Baros District and Petir District, selected through proportionate stratified random sampling. The questionnaire was distributed online through Google Forms and completed voluntarily by the teachers. Data were analyzed using Partial Least Squares Structural Equation Modeling (PLS- SEM) with SmartPLS version 4.0, including evaluation of the measurement model and structural model through a bootstrapping procedure with 5,000 iterations. Results: Principal leadership style and teacher work motivation each had a significant effect on teacher job satisfaction, with path coefficients of 0.715 and 0.450, respectively (p < .01). Job satisfaction was a significant mediator, with indirect effects of 0.402 for leadership style and 0.254 for work motivation on teacher performance. Among the three predictors, job satisfaction had the largest direct effect on teacher performance, with a coefficient of 0.563. The proposed model explained 81.6 percent of the variance in job satisfaction and 90.2 percent of the variance in teacher performance. Conclusion: Teacher performance improves when principals lead adaptively, teacher work motivation is sustained, and the work environment enables teachers to feel satisfied. Job satisfaction serves as an important bridge linking leadership and motivation to day-to-day teaching performance; therefore, these three factors need to be managed simultaneously rather than separately. Limitations: Data were collected from teachers’ self-reports at a single point in time and may therefore be subject to common method bias. The discriminant validity assessment also indicated a high correlation between job satisfaction and teacher performance; thus, findings involving these two variables should be interpreted cautiously. The sample, which was limited to two districts, also restricts the generalizability of the findings to other regions. Contribution: This study provides empirical evidence of the role of job satisfaction as a link between leadership, motivation, and teacher performance at the junior high school level. The findings are useful for principals, the Serang Regency Education Office, and other education researchers seeking to develop more targeted school leadership development policies and teacher welfare programs.
