The purpose of this study was to examine the relationship between the degree of practicing transformational leadership by principals of Zarqa Governorate and their teachers' organizational citizenship behavior. Two hundreds and fifty six basic and high school teachers participated in this study. The results of the study revealed that transformational leadership overall and its dimensions were being moderately correlated to teachers organizational citizenship behavior and its four dimensions: altruism, conscientiousness, civic virtue, and courtesy respectively. On the other hand, transformational leadership overall and its dimensions were weakly correlated to teachers sportsmanship behavior. Furthermore, the results indicated that transformational leadership predicted (0.37) of teachers' organizational citizenship behavior variance and the best predictor was idealized influence (0.47), followed by inspirational motivation (0.36). More over, individualized consideration and intellectual stimulation were found to be insignificant predictor of teachers organizational citizenship behavior. Finally, the study ended by offering a number of recommendations for practice and research.