The study's main goal was to show how principal transformational leadership relates to secondary school teacher's work satisfaction in the Mardan district. Examining the leadership style used by secondary schools’ principals and how they affect secondary school teacher's job satisfaction was the core goal of this study. The study used a quantitative correlational research design. Public sector secondary school teachers are included in the population. Three hundred and ninety-four (394) teachers were chosen as the sample using stratified random sampling. A questionnaire for relationship between a principal' s transformational leadership style and teacher job satisfaction was used to gather the results. The correlation coefficient, mean, and standard deviation were used to examine the data. The study's findings further demonstrated that transformational leadership style has a positive and significant relationship with secondary school teachers' job satisfaction in the district of Mardan. The results indicated that transformational leadership was primarily used by secondary school principals. The study found that teachers' job satisfaction levels with regard to fringe benefits, operating processes, and nature of work were generally high. The other facets remained neutral, with the exception of coworkers and communication dissatisfaction. In order to have happy and effective teachers, the research study recommended that principals make an effort and that competent authorities provide teacher-friendly regulations. The principal of each school should increase faculty involvement in decision-making.