The role of the public school principal has expanded dramatically in recent decades. The expanded role means they are now significant multipliers of effective teaching and have a real opportunity to affect student achievement. Most states have spent recent years working to improve teacher effectiveness, recognizing its importance in improving student outcomes. States have focused considerably less on principals as levers for school improvement, however, research on the importance of school principals in advancing student learning is compelling. Governors have authority over principal preparation programs in their state and are uniquely positioned to address gaps in the systems that influence aspiring and current school leaders at the state and local school district levels. Promising Practices in Boosting School Leadership Capacity: Principal Academies explores principal academies—a tool that governors can add to their policy toolkit to augment preparation and training for aspiring and sitting public school principals.