Rates of self-injurious thoughts and behaviors (SITBs) among youth are high and increasing. Most research has focused on long-term risk factors for SITBs, providing limited insight into when youth are at greatest risk. Real-time monitoring approaches, such as ecological momentary assessment (EMA), offer critical opportunities to understand short-term SITB risk by capturing experiences as they unfold in daily life. This article reviews the implications of real-time monitoring for evidence-based assessment and intervention with high-risk youth. EMA enhances reporting accuracy, identifies dynamic risk and protective factors (eg, sleep problems, social support), and facilitates timely treatment adjustments. These methods are safe, even for high-risk youth, and complement emerging interventions like ecological momentary interventions and just-in-time adaptive interventions, which provide targeted support precisely when needed. Despite their promise, implementation barriers (eg, patient burden) persist. We outline future directions, including integrating real-time data into clinical practice, to improve outcomes for youth SITBs.