The purpose of this R34 NOFO is to provide resources for evaluating the feasibility, acceptability, and safety of novel approaches that are uniquely tailored to the risk profiles of these populations, that will improve outcomes and modify health risk behavior. Resources may also be used for obtaining the preliminary data needed as a prerequisite to a larger-scale (efficacy or effectiveness) services study. The goal is to support research that develops and tests broadly implementable service system interventions to rapidly identify and effectively respond to reduce suicide and suicidal behavior in various groups of at-risk youth. Specifically, the goals of this NOFO are to: 1) develop a multi-level service system intervention that coordinates suicide risk identification, evaluation, and linkage to needed treatment and services for a specifically identified at-risk youth group; 2) test the feasibility and effectiveness of the intervention in detecting and reducing suicide risk and suicidal behavior in the at-risk youth group; and 3) demonstrate the intervention's implementation and potential for future uptake in underserved, under-resourced community settings where additional at-risk youth are most likely to receive care. The ultimate goal of this NOFO is to develop and test the effectiveness of evidence-based strategies for detecting and preventing suicide and suicidal behavior among at-risk youth. It focuses on systems interventions to improve outcomes for youth and is not intended to support the development of new screening tools or assessment instruments.