For more than a century, there has been a growing interest in school climate. Recently, the U.S. Department of Education, Center for Disease Control and Prevention, Institute for Educational Sciences, a growing number of State Departments of Education, foreign educational ministries, and UNICEF have focused on school climate reform as an evidence-based school improvement strategy that supports students, parents/guardians, and school personnel learning and working together to create ever safer, more supportive and engaging K–12 schools. This work presents an integrative review on school climate research. The 206 citations used in this review include experimental studies, correlational studies, literature reviews, and other descriptive studies. The review focuses on five essential dimensions of school climate: Safety, Relationships, Teaching and Learning, Institutional Environment and the School Improvement Process. We conclude with a critique of the field and a series of recommendations for school climate researchers and policymakers.