This study examined the influence of stakeholder collaboration in school improvement planning (SIP) on students’ academic achievement among public junior high schools in Ghana. Employing a quantitative correlational design, data was collected from 284 stakeholders, including head teachers, teachers, School Improvement Support Officers and School Management Committee members selected via the stratified random sampling. Stakeholder collaboration was measured using a validated 12-item Likert scale while student achievement was quantified by Basic Education Certificate Examination (BECE) pass rates for the 2022/ 2023 academic period. Pearson’s product-moment correlation and simple linear regression analyses revealed a statistically significant positive relationship between stakeholder collaboration and students’ academic achievement, underscoring the critical role of collaborative practices in enhancing improved educational outcomes. These findings suggest that strengthening stakeholder collaboration within the SIP process may lead to the improved academic performance, providing valuable empirical evidence for the Ghanaian educational context and indicating the need for further research into other factors that may influence student success