The basic aim of the research at hand was to investigate the effects of conflict management styles of school principals on teachers' job performance. To meet the major objective of the study, the targeted population was comprised of public sector secondary schools in the Punjab province. As the population was most scattered so the researchers used multi-stage sampling techniques to approach the whole population. At the 1st stage Gujranwala division was randomly selected through simple random sampling technique. At the 2nd stage, 176 secondary schools from three districts viz. Narowal, Gujranwala, and Sialkot were selected randomly. Among these 176 schools, 100 were male and 76 were female secondary schools. At the 3rd stage, 532 SSTs were randomly selected from the respective schools. It was a quantitative study and a survey technique was used to conduct it. The researchers used two questionnaires namely, FOCI for measuring school principals' styles of managing conflicts and TPES for measuring their respective teachers' job performance. Using MS Excel 2010 and SPSS version 24, statistical procedures (t-test, ANOVA, and regression analysis) were applied to analyze and interpret the data. It was determined that there was a strong correlation between teachers' job performance and the conflict management styles used by school leaders. Moreover, in conflict management styles, integrating and obliging styles had a positive effect whereas avoiding, compromising and dominating styles negatively effects teachers' job performance. The researchers have recommended that mix method research may be applied to validate the results of the study. Beyond further research, it is suggested that school Principals should be trained for better conflict management.