Despite efforts to achieve UNAIDS 95-95-95 targets, marked deficits remain in HIV testing, antiretroviral therapy (ART) adherence, and viral suppression among a growing number of persons living with HIV (PLWH). Gaps in HIV treatment success are particularly pronounced in the United States (US) South and Northeast, specifically, Alabama (AL) and New York City (NYC), the two high priority settings for our study. These suboptimal HIV-related health outcomes occur at a time when clinicians have limited time and the US healthcare system remains fragmented, exacerbating the challenges inherent in the lives of poor or stigmatized groups, such as PLWH. Therefore, the development and evaluation of interventions using a resource-savvy cadre of community health workers (CHW) holds promise for addressing these challenges. Yet, gaps exist in the CHW literature, and research is needed to bring CHW interventions to scale and to ameliorate the large gaps in the US HIV Care Continuum, particularly in Ending the HIV Epidemic (EHE) priority locations. In response, our highly experienced study team will address limitations in current research focused on CHW interventions to improve viral suppression and ART adherence. We propose to build on our strong preliminary data and directly respond to RFA-NR-20-002 by strengthening our CHW intervention, Birmingham Access to Care (BA2C), through the use of our existing mobile health (mHealth) approach, WiseApp. The literature and our preliminary work support the scientific premise that the addition of WiseApp to the CHW intervention guided by a rigorous theoretical model of supportive accountability will allow PLWH to be better able to self- manage their ART regimens while CHW monitor their ART adherence in real-time. This will ultimately lead to an improvement in viral suppression and ART adherence. The proposed study blends the strengths of the BA2C and WiseApp interventions to test a rigorous and reproducible CHW intervention, Community Health Workers And MHealth to ImProve Viral Suppression (CHAMPS), to improve viral suppression and ART adherence. The proposed study will test the intervention’s clinical efficacy and assess implementation factors through the following specific aims with virally unsuppressed adult PLWH (n=150 in AL and 150 in NYC): 1 Conduct a randomized controlled trial (RCT) to assess the efficacy and sustainability of CHAMPS on viral suppression (primary outcome) and ART adherence (secondary outcome) compared to the standard of care (standard of care, control group) over 6 and 12 months. 2) Identify mediators (self-efficacy, motivation expectancies, self-regulation skills, HIV-related stigma) and moderators (depression, anxiety, substance use) of CHAMPS on study outcomes. 3) Guided by the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) framework, identify multi-level factors associated with successful implementation of CHAMPS to inform future implementation and scale-up of CHAMPS. Finding...