Over the past decade, teacher autonomy has become increasingly significant due to its positive impact on educational outcomes. The study explores the mediating role of teachers' academic optimism in the relationship between school principals' empowering leadership and teacher autonomy. In this study, we proposed teachers' academic optimism as a mediator in the relationship between empowering leadership and teacher autonomy. Data obtained from a sample of 384 teachers in Türkiye were analysed according to structural equation modelling. The results showed that school principals' empowering leadership positively and directly predicted both teachers' autonomy and their academic optimism. The results also indicated that teachers' academic optimism positively and directly predicted teacher autonomy. In addition, academic optimism was found to significantly mediate the relationship between empowering leadership and teacher autonomy. The findings highlight the importance of empowering teachers and strengthening their academic optimism as a means to enhancing their independent actions and decision-making capabilities. Our findings provide practical recommendations for developing principals' empowering leadership behaviours and in the enhancement of their academic optimism.