Evidence from high-income countries suggests that the quality of school leadership has measurable impacts on teacher behaviors and student learning achievement. However, there is a lack of rigorous evidence in low-income contexts, particularly in Sub-Saharan Africa. This study tests the impact on student progression and test scores of a two-year, multi-phase intervention to strengthen leadership skills for head teachers, deputy head teachers, and sub-district education officials. The intervention consists of two phases of classroom training along with follow-up visits, implemented over two years. It focuses on skills related to making more efficient use of resources; motivating and incentivizing teachers to improve performance; and curating a culture in which students and teachers are all motivated to strengthen learning. A randomized controlled trial was conducted in 1,198 schools in all districts of Malawi, providing evidence of the impact of the intervention at scale. The findings show that the intervention improved student test scores by 0.1 standard deviations, equivalent to around eight weeks of additional learning, as well as improving progression rates. The outcomes were achieved primarily as a result of improvements in the provision of remedial classes.