Abstract Young adult lesbian women are twice as likely to be overweight and obese as their heterosexual peers and Black women are similarly more likely to be obese than White women. These minority women are thus more prone to obesity-related comorbidities including heart disease, stroke, and type 2 diabetes, which are leading causes of death in the U.S. Binge eating behaviors (overeating, loss of control of eating) contribute to obesity and are particularly prevalent in young adult women. Despite well documented disparities in binge eating, little is known about contributing factors in lesbian women, and in particular racial minorities. In studies of young women where sexual orientation is not known, assessed, or reported (hereafter referred to as general samples), research demonstrates binge eating is associated with affective states, social processes, and health behaviors. Studies by our group and others using mobile technology-based ecological momentary assessment (EMA) have examined how daily affective and social experiences influence young women's eating in everyday life. These studies were conducted with general samples of primarily White women; how affective states, social processes, and health behaviors in daily life impact lesbian women's binge eating remains unclear. Consistent with minority stress theories, preliminary data also suggest sexual minority stress ? or the stress people from stigmatized groups are exposed to due to their marginalized social status ? likely influences binge eating in lesbian women, but the role of unique minority experiences in binge eating has not been examined using EMA. Race, eating-related factors, and sexual minority-specific factors may also moderate daily associations, but have not been fully explored. In particular, implications of having intersecting sexual- and racial-minority identities (i.e., being a Black lesbian women) on binge eating have yet to be considered. To address these limitations in the binge eating and sexual minority literatures, the proposed study examines affective, social, health behavior, and sexual minority-specific factors associated with binge eating in natural settings. Young adult lesbian (n=150, 50 Black) and heterosexual (n=150, 50 Black) women ages 18-30 who engage in binge eating behavior will complete brief smartphone-based EMA surveys five times daily and in response to binge behaviors for two weeks. Study aims include examining how daily affective, social, and health behavior factors impact lesbian women's eating, and how sexual minority-specific experiences uniquely contribute to binge eating in daily life. We will also explore how race moderates these associations. The EMA design allows examination of daily processes in natural settings, and including racially diverse lesbian and heterosexual women allows identification of factors that contribute to disparities. This study fills research gaps by expanding understanding of general and sexual minority-specific factors that contribute to binge eating in daily life, and the role of race in these associations. Such information is critical for informing the development of culturally tailored interventions for lesbian women, with the ultimate goal of reducing binge eating and obesity disparities.