This Learning Policy Institute report reviews a broad body of neuroscience, science of learning, and child development research to examine how schools can design positive environments that promote holistic development and achievement for all children, including students living with trauma. This analysis of literature suggests positive school environments (1) foster supportive environmental conditions that create a positive school climate and foster strong relationships and community; (2) facilitate social and emotional learning that fosters skills, habits, and mindsets that enable academic progress and productive behavior; (3) provide productive instructional strategies that support motivation, competence, self-efficacy, and self-directed learning; and (4) extend individualized supports that enable healthy development, respond to student needs, and address learning barriers. The report describes strategies schools and educators use to create schools that support healthy development for young people based on three recommendations: (1) focus the system on developmental supports for young people, (2) design schools to provide settings for healthy development, and (3) ensure educator learning for developmentally supportive education.