PurposeThe present study aimed to investigate whether the sub-dimensions of transformational leadership are differently influenced by middle-leaders’ personality traits from the Big Five typology, namely, extraversion, conscientiousness, openness to experience, agreeableness, and neuroticism, and whether the sub-dimensions of transformational leadership influence teachers' professional and organizational commitment differentially.Design/methodology/approachData were collected from two sources: 114 middle-leaders and 282 teachers randomly chosen from elementary schools in Israel. Hierarchical regression analyses and structural equation modelling were used to test the research hypotheses.FindingsFirst, the findings indicated that the teachers perceived their middle-leaders as transformational leaders without distinguishing between the sub-dimensions. Second, transformational leadership was positively correlated to teachers' professional and organizational commitment. Finally, positive relationships were found between the middle-leaders personality traits of agreeableness and openness to experience and teachers’ commitment. The study findings point to two paths to facilitate teachers' professional and organizational commitment, either through the middle-leaders transformational leadership or their personality.Originality/valueAlthough recent research has shown that leaders' personal traits are critical components in leading a team effectively and promoting employee behaviors, few studies in the educational context have focused on the differential impact of the Big Five typology on middle-leaders’ tendency toward the sub-dimensions of transformational leadership (TL) and its implications for teachers' commitment. By integrating research from both educational and non-educational literature, the goal of the present study, then, is to address these important yet relatively unstudied issues.