This article provides a brief history of the development of the federal model of school threat assessment, which was created by the U.S. Secret Service and U.S. Department of Education based upon findings from their empirical research on school shootings across the USA. The article reviews the major findings from that behavioral research, which demonstrates how it is possible to prevent school shootings and other targeted violence in school. The article also describes the components of this evidenced-based federal model and implementation guidance for schools and districts within the USA as well as other countries. The article concludes with the lessons learned by the authors and their colleagues in using the federal school threat assessment model to handle individual school threat cases and in training tens of thousands of other school, law enforcement, and mental health professionals how to use threat assessment to prevent school violence.