Active shooter response trainings are designed to train school personnel and students on how to respond to emergencies in ways that will (in theory) save lives (King & Bracy, 2019). As these trainings are increasing in prevalence in educational settings (Cox & Rich, 2018), it is increasingly likely that individuals who work with schools and school-aged children will be asked to treat, advise, educate, or counsel individuals who are impacted by these trainings. However, there are substantial gaps in the literature on the efficacy and impact of these trainings on students that hamper our ability to provide evidence-based services. This review first identifies the basic structure of active shooter training format and content. Next, we review the available outcome research on safety, preparedness, stress, and long-term mental and emotional health based on training format and content. Finally, we identify some specific characteristics (participants of color, children of different ages, adverse experience and trauma history) that may guide thinking of individual differences in these trainings’ impact. Finally, we detail important considerations that support best practice decision making and next steps.