Suicide is a leading cause of death among adolescents and there are few scalable interventions to reduce suicide risk. Since the start of COVID-19, demand for mental healthcare services, including those for suicidal thoughts and behaviors (STB), has surged. As a result, waiting times for mental healthcare have increased. This reality is particularly troubling in underserved communities, where access to mental healthcare is historically challenging, and rates of STB among youth are on the rise. Thus, there is a dire need to develop effective interventions for people at risk for suicide who experience barriers to accessing mental healthcare. Following established implementation science frameworks, this application for the Early Career Researcher Grant proposes to adapt and examine the feasibility of our online suicide intervention, Supporting Wellbeing with Everyday Experiences of Peers (SWEEP), for diverse adolescents from the Bronx, NY. Existing evidence in adults indicates that SWEEP, a digital narrative-based bibliotherapy involving reading about others’ struggles with and recovery from STB, helps reduce risk for STB. Importantly, SWEEP is a low-cost, brief (less than 10 minutes per day) intervention that can be accessed from any smartphone, reducing barriers to clinical care. In the proposed study, we plan to involve community stakeholders (diverse adolescents from underrepresented communities in the Bronx, NY) in the adaptation of SWEEP (Aim 1, n=10), centering their lived experience with STB as a therapeutic resource to help high-risk, suicidal youth. After integrating feedback from these stakeholders, we will launch a feasibility trial to identify optimal ways to administer the intervention for diverse adolescents (Aim 2, n=6). Finally, we will conduct an open trial to test hypothesized benefits of SWEEP for reducing suicidal thoughts, social isolation, and hopelessness among diverse adolescents experiencing STB (Aim 3, n=40). In both the feasibility trial (Aim 2) and subsequent open trial (Aim 3), we will examine changes in suicidal thoughts, social isolation, and hopelessness using ecological momentary assessment (EMA). The use of EMA will increase the study’s ecological validity and enable detailed examination of the time course of changes in the three hypothesized intervention targets. Results from this study will help to establish preliminary efficacy for this accessible digital intervention that uses the lived experience of peers to support diverse youth at risk for suicide. Further, these findings will inform the development of a larger-scale randomized controlled trial to evaluate the benefits of SWEEP in a range of clinical settings (e.g., following emergency department discharge).