Sexual minority women (SMW) are at increased risk of elevated body mass index (BMI) compared to heterosexual women, increasing their vulnerability to chronic diseases. Nonmonosexual SMW appear to be at additional risk for elevated BMI, likely due to unique sexual minority stressors. A total of 437 SMW and heterosexual women completed a cross-sectional, online survey including self-report measures of sexual orientation dimensions, weight, psychological distress, and eating behaviors. We investigated relations among these variables to better understand disparities in self-reported BMI based on sexual orientation and sexual orientation discordance (SOD). SMW self-reported more psychological distress, more binge eating, and higher BMIs than their heterosexual peers, with nonmonosexual groups of SMW often reporting the highest values. SOD was positively associated with psychological distress. SMW-particularly nonmonosexual SMW-are at increased risk for psychological distress, binge eating, and elevated BMI relative to heterosexual peers. Future research should further elucidate mechanisms for these disparities.