Purpose of the study: This study aims to determine the ability of the principal in carrying out Instructional Leadership to improve teachers' teaching performance so that it has an impact on improving the character of students.
Methodology: The type of this research is evaluative descriptive. The subjects selected by purposive sampling and triadic included 15 principals, 150 teachers, and 450 students in Yogyakarta. The data collection techniques using observation, interviews, questionnaires, and documentation. The data analysis techniques using mixed methods. The quantitative data were analyzed using descriptive statistics and linear regression. In contrast, the qualitative data were analyzed using Miler and Huberman's theory, which included four stages: reduction, display, triangulation, and conclusion.
Main Findings: First, mild juvenile delinquency is still practiced by students. Secondly, character strengthening is done through an extracurricular program, orderly book socialization, cooperation with external parties. Third, the instructional leadership ability of principals is still low. Fourth, the magnitude of the influence of Instructional Leadership in changing students' characters obtained a percentage of 12%, while other factors influence 78 %; and the inhibiting factor for instructional leadership of school principals is the lack of collaboration between schools and parents.
Applications of this study: The results of this study can provide significant benefits in the discipline of character education and educational psychology. The school leaders can use the findings in this study to tackle juvenile delinquency in junior high school.
Novelty/Originality of this study: It turns out that to reduce and eliminate juvenile delinquency is not enough just with Instructional Leadership. The most significant factor that can help minimize adolescent familiarization is the existence of good cooperation between parents and teachers or the school.