The study aims to disclose the relationship between principal's instructional leadership (PIL) and teacher self-efficacy (TSE) through a meta-analytical synthesis. The meta-analysis covers 24 studies, which represent 9178 teachers, and examines the relationship between PIL and TSE. It was established that publication bias was not a significant problem in the study. The random-effects model was used to measure the average effect size. The result demonstrated that a moderate relationship exists between PIL and TSE. Additionally, subgroup analysis was performed according to the location of the studies and publication types. Analysis revealed that the country where the research was conducted and publication type did not cause differentiation. Moreover, the relationship between PIL behaviors and TSE beliefs illustrate that school principals can improve TSE beliefs by exhibiting instructional leadership behaviors. In turn, student achievement can be improved by enhancing the classroom behaviors of teachers through instructional leadership. Policymakers should be aware that school principals can increase the professional development of teachers and the academic success of students through instructional leadership practices and organize managerial training for school principals to improve their instructional leadership practices.