Principals play a key role in developing teachers’ capacity to develop deeper learning classrooms. They are responsible for providing developmentally grounded and personalized learning opportunities to develop the skills and knowledge teachers need to teach for deeper learning, reflecting the opportunities they expect teachers to provide in classrooms. They must establish the time and structures in the daily or weekly schedule to build collaborative professional communities that enable teachers and other school staff to pool their expertise and support one another’s growth. And, they are responsible for setting up accountability systems that emphasize good instructional practices, continuous improvement, and equity, with the explicit purpose of adult development and empowerment.