Abstract: Automotive industry has played an important role in both regional and global economies. Thailand has become a significant center for automotive parts manufacturing due to its low labor and production costs. In the new era, business leaders and managers are important in creating organizational success in the competitive environment and in implementing change. Also, lean manufacturing has become a critical management tool because it offers an efficient system that enhances operations processes by reducing waste, which results in sustainable growth. This research aims to analyze the relationships among leadership, lean and performance in Thailand’s auto parts industry. The survey was conducted by administering questionnaires to 540 managers. Then, structural equation modelling was employed for the analysis. The latent variables were leadership, lean manufacturing practices and firm performance. The results suggest significant relationships among leadership, lean manufacturing practices and firm performance. Performance was most affected by lean manufacturing practices followed by leadership. Leadership also had more of an indirect influence on firm performance than a direct effect. This research contributes to the knowledge regarding the relationships among leadership, lean manufacturing practices and firm performance, facilitating executives and business owners in their process of obtaining desirable organizational performance. To achieve a high level of firm performance in quality, timeliness and efficiency, the organization must concentrate on idealized influence, inspirational motivation, intellectual stimulation, low setup, controlled processes and productive maintenance.