Influence of Principals’ Management Practices on Kenya Certificate of Secondary Education in South Kinangop, Nyandarua County,Kenya

School principals play a crucial role in managing education and influencing student academic performance. Despite continuous curriculum reforms and teacher training initiatives, student performance in the Kenya Certificate of Secondary Education (KCSE) remains below expectations. This study aimed to examine the impact of principals’ management practices on KCSE performance in South Kinangop Sub-County, Nyandarua County. Specifically, the study analyzed the effects of principals’ discipline management, provision of teaching and learning resources, instructional supervision, and parental involvement on students’ academic outcomes. Anchored on Systems Theory and Education Product Theory, the study employed a mixed-methods research approach, integrating both qualitative and quantitative data. Data were collected from 28 principals, 401 teachers, and 3,111 students in public secondary schools within the sub-county using structured questionnaires and interviews. Quantitative data were analyzed using descriptive statistics and Spearman’s Rank Correlation (α = 0.05) in SPSS version 25, while qualitative data underwent thematic analysis. Results indicated a significant positive correlation between principals’ discipline management (r = 0.62), provision of teaching and learning resources (r = 0.57), instructional supervision (r = 0.65), and parental involvement (r = 0.54) with KCSE performance (p