The present study aimed to examine the impact of leadership styles (transformational & transactional) of the head of departments on employees (teachers) performance working in the academic department of higher educational institutions in Khyber Pakhtunkhwa, Pakistan. In similar vein, current study also examined mediating role of organizational justice and culture in relationship between leadership styles and teachers’ performance. For this purpose, data was collected from the both teachers and head of departments in the selected HEIs. The same data was then analyzed by using different statistical tools like correlation, regression, mediation and test of significance. In this regard, correlation analysis shows that all research variables are significantly correlated (table 4.14), wherein, correlation between transformational style and employees performance is (R=.915 & P-value=.000), transactional style (R=.816 & P-value=.000), organizational justice (R=.815 & P-value =.000) and organizational culture (R=.849 & P-value =.000). Similarly, cause-n-effect relationship shows that there is significant impact of predictors on criterion variable (table 4.15), wherein, the results showed that the transformational leadership is stronger predictor of employees’ performance (p- .000) as compared to transactional leadership (.020). Likewise, the mediation results (four models, table 4.40) shows that mediating variables (organizational justice & culture) partially mediate the relationship between the predictors and the criterion (tables 4.16 to 4.30a). In same line, test of significance shows diverse results about mean differences among demographic groups of respondents (tables 4.32 to 4.39). The results show that out of fourteen (14) hypotheses, eleven (11) were accepted and three (3) were rejected. However, findings of current study were positioned in Chapter 5, where these findings (current study) were compared with existing research (previous research) findings. In light of this positioning, conclusion were drawn based on certain recommendations and implications.