Modified Project Summary/Abstract Section Over 70% of Americans have a body mass index (BMI) classified as overweight or obesity. Weight-related stressors (e.g., negative perceptions and treatment based on body size) are experienced more frequently by certain groups and those with higher BMIs, and can contribute to unhealthy behaviors, and increased disease risk, making the study of these experiences essential to improving health outcomes across the broader population. Sexual minority women (SMW; i.e., women with sexual orientations other than heterosexual) are up to twice as likely to live in larger bodies and experience weight-related stressors compared to men and heterosexual women. Weight-related stressors, the NIMHD research framework, and the minority stress model, which posits that some groups, such as SMW, are at increased risk for stress due to multi-level contextual stressors, can be applied to help delineate risk and protective factors associated with population-level variability in obesity. Greater knowledge of these factors, particularly for at-risk groups like SMW, can offer insight into broader mechanisms influencing obesity risk and enhance public health strategies for population-based health. Research on obesity among women or the primary behavioral drivers of overweight/obesity (i.e., energy-balance behaviors, unhealthy weight-control behaviors, physical inactivity) has given little attention to weight-related and contextual stressors and little consideration of belonging to multiple disparity populations, often grouping individuals analytically that obscure important differences. Among the research on weight-related stressors, energy-balance behaviors, or their health correlates (e.g., disordered eating), there is an overreliance on cross-sectional, retrospective self-report, or semi-annual longitudinal designs. These studies provide knowledge foundation, but are limited in the data they can provide. Experience sampling methods (ESM) can advance our understanding by identifying temporally proximal risk factors for behavioral health disparities and disentangling risk factors from correlates. This exploratory sequential mixed methods study aims to delineate factors and mechanisms that may be associated with behavioral risk among women with non-heterosexual orientation and belonging to a racial/ethnic minority population to inform a more comprehensive understanding of population-level variability in weight-related health. Aim 1 utilizes a qualitative life history approach to identify preliminary barriers and facilitators to health cognitions and behaviors. Aim 2 uses ESM to test the preliminary model identified in Aim 1 and examine relationships between contextual and weight-related stressors and behaviors in real time in the natural environment among SMW. These aims support my training plan with expert mentors and training in: multi-level contextual influences on behavioral health (Training Aim 1); mixed methods data collection ...