Project Summary/Abstract Obesity is the most prevalent preventable risk factor for cardiometabolic morbidity and mortality in the US. Additionally, obesity is more prevalent among racial/ethnic minorities whose rates continue to increase. Racial/ethnic disparities in obesity are influenced by social determinants of health that contribute to social disadvantage at multiple levels of influence. Among their influences, social determinants of health can interfere with the diet and activity behaviors that are the primary drivers of obesity and the targets of weight management interventions. Interventions need to account for these potential influences of social disadvantage. Mobile Health (mHealth) interventions are particularly promising because they have the reach and efficiency for equitable population-level dissemination. However, the degree to which social disadvantage interferes with mHealth treatment efficacy has not been well-studied, and so it is unclear whether mHealth weight management intervention produces equitable outcomes across sociocultural contexts. Research is needed to explore whether social disadvantage constrains the benefit derived from mHealth intervention, in order to inform potentially needed optimization. This project will leverage multiple synergistic research methods that span the intervention evidence spectrum to evaluate this question. A systematic review and meta-analysis will provide a comprehensive, rigorous overview of research literature on how mHealth obesity treatment effects may be moderated by socioenvironmental context and disadvantage. Secondary quantitative analyses of two previously conducted mHealth weight loss trials will evaluate the extent to which multilevel social determinants of health moderate improvements in health behaviors. Finally, qualitative interviews and analysis will be used to evaluate racial/ethnic minority participants’ perceptions of barriers and facilitators to engagement in mHealth weight management. Together, these synergistic methods to be learned and applied in this fellowship span the analytic spectrum. Their integration will build a coherent foundation upon which we can advance mHealth interventions for weight management among racial/ethnic minorities.