Purpose: The purpose of this study is to investigate gender differences in transformational leadership and social exchange outcomes in public primary schools in Tehran, Iran. Design/methodology/approach: A total number of 400 teachers and 77 principals completed questionnaires. Multivariate analysis of variance was performed to determine gender differences in transformational leadership dimensions including idealized influence, inspirational motivation, intellectual stimulation, and individualized consideration. Also, multiple regression was used to identify the impact of dimensions on three social exchange outcomes including procedural justice, trust in principal, and organizational citizenship behaviors of teachers. Findings: Results showed that female principals as compared to male principals obtained significantly higher scores on transformational leadership dimensions and the greater amount of transformational behaviors displayed by them has accompanied with the greater prediction of social exchange outcomes. Research limitations/implications: This study suggests that there are some benefits associated with having female principals and schools could particularly benefit from developing principal training programs that focus on developing female principals qualities. Some following limitations could be avoided in future research: only relying on teacher rating of principal, possible effect of the teacher's gender on the relationship of transformational leadership with social exchange outcomes, and principal-teacher gender mach limitation in rating principals. Originality/value: Given the limited studies conducted on gender differences in transformational leadership and social exchange outcomes in schools and in Iran, this study provides empirical insights and extends this line of inquiry in public schools. This study confirms the results of previous studies which they have found females as more transformational than male counterparts and also provides new finding surrounding social exchange outcomes. These results could be influential in encouraging Iranian policy makers to further acknowledge women administration in public schools.