The quality of education is a major concern in the Maldivian education system. Previous literature posits that effective leadership is critical for the realization of school goals. As such, instructional leadership is claimed to contribute to the teaching and learning process of the school. The purpose of this research is to determine the impact of deputy principal's instructional leadership on school effectiveness in public schools in Malé, the capital city of Maldives. It also aims to analyze the interaction effect of school level on the relationship between instructional leadership and school effectiveness. A quantitative research approach is selected for this study. The data was collected using a survey questionnaire. The sample consisted of 359 teachers working in the public schools of the capital city, Malé, who were selected through stratified random sampling. Structural equation modeling (SEM) was used to analyze the conceptual relationships. The findings revealed that deputy principal's instructional leadership has a direct and positive relationship with school effectiveness. The moderation test indicated that school level moderates the relationship between deputy principal's instructional leadership and school effectiveness, where the interaction effect is higher at secondary level compared to primary level. The results present many implications towards theory and practice of instructional leadership and school effectiveness.