Modified Project Summary/Abstract Section Youth today face a high risk for serious mental health problems (e.g., suicidality, depression, anxiety), which is exacerbated by significant barriers to mental health care. mHealth interventions have been developed to address the needs of youth and their caregivers, but are underutilized. Lay health worker (LHWs) are individuals who use their lived-experience, language and/or culture to support patients and/or families in mental health service access and engagement. In response to PAR-22-109 and NIMH Strategic Objective 4: Strengthen the Public Health Impact of NIMH-Supported Research, we seek to increase mental health care access for youth by enhancing the dissemination of evidence-based mHealth interventions through the design of a training intervention for LHWs – Getting Access on the INternet (GAIN). Specifically, we will use human centered design (HCD) to adapt a mental health provider training intervention (developed by MPI Price K23MH124670) based on data from MPI Barnett (R01MH117123-02S1) on the needs of youth and their parents receiving LHW services. The proposed R21 study involves working with community partners (i.e., youth, their parents, and LHWs) to (Aim 1) co-design GAIN - a mechanism-driven training intervention for LHWs, then (Aim 2) build the LHW training intervention via usability testing. This study will result in an acceptable and refined training intervention ready for testing in a large, multisite R01 study.