Teacher productivity at the secondary school level has been a concern to stakeholders. This concern could be associated with principals’ leadership style, which appears not to be given a premium place in the school system. This study investigated the influence of principals’ traditional leadership styles on teacher productivity in Lagos State Public Secondary Schools, Nigeria. Traditional leadership styles, including autocratic, laissez-faire, and democratic, were examined in relation to their impact on teacher performance, motivation, classroom management, and overall productivity. Using a descriptive survey design, data were collected from 900 respondents comprising principals and teachers selected across Lagos State Public Secondary Schools in six Educational Districts. Findings revealed that democratic leadership style had a positive effect on teacher productivity, while autocratic and laissez-faire styles had negative impacts. The study concluded that leadership style significantly determines teacher effectiveness, and recommended training for school principals on the participatory leadership model.