Students exposed to school violence are at risk for adverse short- and long-term impacts on physical and psychological well-being. Behavioral threat assessment (BTA) is a strategy used to identify, assess, and manage student threats to mitigate the risk of violence. However, anecdotal BTA cases have highlighted how BTA processes can negatively impact student mental health, including for students receiving special education services. Utilizing the Population/Concept/Context (PCC) framework, this scoping review examined previous research on BTA in US K-12 schools to identify what BTA outcomes have been evaluated and examine recommendations for future BTA research. Academic databases and gray literature were searched for English-language studies that primarily focused on BTA outcome measurement in K-12 schools in the USA from April 20, 1999, to March 31, 2023. Summative and conventional content analyses were utilized to code BTA outcome and recommendation data, respectively, from 28 eligible studies. The most frequently measured outcomes were disciplinary, while some non-disciplinary outcomes were also studied. Most recommendations across studies focused on the approaches to implementing BTA, research methodology, responses to student threats, long-term effects of BTA on students, and outcome disparities across demographics. While there is promising evidence for using BTA in K-12 schools, future research is needed to expand its generalizability and study other outcomes associated with BTA, such as fidelity to BTA frameworks and mental health outcomes.