This study aimed to explore the impact of transformational leadership practiced by secondary school principals in the southern governorates of Palestine on teachers’ perceived organizational support. The study adopted a descriptive, analytical, and causal approach, and the sample consisted of (510) male and female teachers selected through stratified random sampling. A questionnaire was used as the primary data collection tool. The findings revealed that the degree to which secondary school principals in the southern governorates of Palestine practiced transformational leadership reached a relative weight of (78.74%), indicating a high level of practice. Similarly, the level of perceived organizational support among teachers reached a relative weight of (81.56%), also reflecting a high degree. Moreover, the results indicated a statistically significant impact of all dimensions of transformational leadership—idealized influence, inspirational motivation, intellectual stimulation, and individualized consideration—on teachers’ perceived organizational support, with an overall effect size of (81.6%), which is considered substantial. Based on these findings, the study recommended designing specialized training programs to develop transformational leadership skills among school principals, and providing targeted, up-to-date professional development opportunities aligned with the actual needs of teachers. Keywords: Transformational leadership, Perceived Organizational Support