Purpose: School principals should create a positive school climate through instructional leadership behaviors and support teacher autonomy to reach their ultimate goals. This study examines the relationship between the instructional leadership behaviors of school principals and teacher autonomy, testing the mediating role of school climate and the moderator role of teacher seniority. Design/methodology/approach: This cross-sectional study tests the relationships between the variables with structural equation modeling. By stratified sampling method, research data from 739 teachers in six central districts of Ankara during the 2022-2023 academic year. Findings: Results showed that school principals' instructional leadership behaviors, teacher autonomy, and perceptions of school climate were above average. The study also indicates that the instructional leadership behaviors of school principals are positive and significant predictors of teacher autonomy and school climate and that school climate is a positively significant predictor of teacher autonomy. Moreover, school climate partially mediates the relationship between instructional leadership and teacher autonomy, and teacher seniority has a moderator role. Research limitations/implications: This study is limited to the opinions of the teachers working in the official primary, secondary and general high schools in the districts of Ankara in the 2022-2023 academic year on the instructional leadership of the school principals, the teachers' perceptions of autonomy and the school climate. It has been observed that there is a relationship between the instructional leadership behaviors of school principals and teacher autonomy. It can be said that the instructional leadership behaviors of school principals support teachers to exhibit autonomous behaviors in instructional strategies and processes, curriculum, classroom management, professional development and communication. Practical implications: It is seen that the instructional leadership behaviors of school principals affect teacher autonomy through school climate. It can be said that with the instructional leadership behaviors of school principals, the school climate is more democratic, success-oriented, sincere, supportive of teacher leadership and transforming conflicts into an opportunity for school development, thus affecting teachers' areas of autonomy. We can say that with the development of teachers' autonomy, more effective instructional strategies and instructional processes are developed, the curriculum is transferred with more permanent teaching techniques, professional communication is transformed into collective actions and more comprehensive studies are planned and implemented. Originality/value: This study will extend the literature by revealing the complex link between instructional leadership, teacher autonomy, school climate and teacher seniority. Furthermore, this study estimates how these complex interactions emerge in non-western cultures with centralized educational structures.