Much of the fresh literatures on effective schools have been emotionally connected to the leadership role of the school principals and teachers’ job satisfaction to the achievement of organizational outcomes. Transformational leadership theory has pitched these relations in a new perspective where supporters have claimed that transformational leaders are more able to satisfy their followers to achieve their organizational objectives compared to other styles of leadership. This study was aimed to determine the impact of transformational leadership styles of principals on job satisfaction of secondary schools teachers. The major objectives of the study were: (1) to investigate the level of transformational leadership styles of principals; (2) to identify the level of job satisfaction among secondary schools teachers and (3) to examine the relationship between transformational leadership styles of principals and job satisfaction of secondary schools teachers. To achieve the objectives, the hypotheses were tested. This study was delimited to secondary schools teachers of government male high and higher secondary schools in Khyber Pakhtunkhwa, Pakistan and all government teachers enrolled in different programs at Northern University, Nowshera. It was descriptive co relational study and survey method was used for data collection. The population for the study was all secondary schools teachers of 1166 government male high and higher secondary schools and all government teachers enrolled in various programs of Northern University in KPK. Using a convenient sampling technique, a sample of 1050 teachers from 140 schools, 20 each of seven selected districts on the basis of cultural background, was taken as sample-I. Another sample of 100 government teachers enrolled in different programs from Northern University was taken as sample-II. Two instruments i.e. MLQ and JSS were used for the collection of data in this study. Data were collected through personal visits. Data were analyzed by applying mean, standard deviation, ttest and Pearson’s correlation. The findings of the study were that principals of male high and higher secondary schools showed higher level of transformational leadership styles. The level of job satisfaction of secondary school teachers was found at a moderate level. Both the samples showed a positive and significant relationship between transformational leadership styles of principals and job satisfaction of secondary school teachers. The findings revealed no major differences in the results of collected data from two different environments and locations.