Significance. For many people living with HIV (PLWH), heavy drinking and/or problems related to alcohol use adversely impact their health and their HIV care. Thus, interventions to reduce alcohol use and improve HIV care outcomes among PLWH are urgently needed. Career Development Plan. Dr. Knox’s training will include developing critical skills in intervention research and implementation science, and substantive training in HIV care and treatment. This will be achieved through a plan that includes seminars, workshops, coursework, conferences, and tailored mentoring. These activities will help Dr. Knox become an independent investigator with a research program focused on understanding and addressing HIV and alcohol use. Research Plan. In Aim 1, Dr. Knox’s proposed research involves conducting formative work to inform the development of an intervention that addresses alcohol use and HIV care outcomes. The intervention will combine components from two distinct and potentially complementary, evidence-based interventions (EBI) that are brief, clinic-based and theory-driven. The first EBI improves HIV care outcomes among PLWH by involving a member of their social network to support them in HIV care. The second EBI addresses alcohol use by using mobile health (mHealth) technology to engage PLWH daily in self-monitoring relative to drinking reduction goals formed during a brief, motivational component of the baseline intervention session. In Aim 2, the information from this formative work will be synthesized with the help of consultant workgroups made up of PLWH and implementation partners. The product of Aims 1 and 2 will be a new intervention that leverages both social network support and mHealth technology to reduce alcohol use and improve HIV care outcomes among PLWH. It will be administered as a single-session baseline intervention with follow-up check-ins after 30-days and 60-days. In Aim 3, the new intervention will be pilot tested to assess its potential efficacy, acceptability, feasibility and implementation against a randomly assigned control condition among 60 PLWH. The results of this pilot test will inform the development of an R01 proposal for a fully powered randomized controlled trial to evaluate the efficacy and implementation of the developed intervention. Mentorship. A team of expert investigators in alcohol and drug use, HIV, intervention development, implementation science and mixed methods will support this research. Public Health Impact. The project aims to improve the health of PLWH and improve HIV care outcomes. This has the potential to, in turn, reduce incidence of new HIV infections. These are all high priority research areas of the NIH Office of AIDS Research, and will support works towards achieving important Ending the HIV Epidemic milestones.