This study examined the extent of instructional leadership and its influence on student achievement in private secondary schools. Specifically, it assessed four core domains of instructional leadership-vision and goals, support for teaching. professional development opportunities, and instructional strategies-and measured student achievement based on academic performance and grade point average. Utilizing a descriptive-correlational research design, data were collected from 54 respondents through a validated survey instrument. Descriptive statistics. Pearson correlation, and linear regression were employed for data analysis. Findings revealed that instructional leadership was extensively practiced across all domains, with the highest ratings observed in vision and goals and professional development. Student achievement was also perceived to be extensive, particularly in academic performance. A strong positive and statistically significant correlation was found between instructional leadership and student achievement, indicating that effective school leadership is vital in improving learner outcomes. Regression analysis further identified support for teaching and professional development opportunities as significant predictors of student achievement, though both demonstrated a negative influence, suggesting potential gaps in implementation or relevance. While conceptually important, vision, goals, and instructional strategies did not yield statistically significant effects.