Background: Although high educational attainment is linked to better health and lower health risk behaviors, this effect may be systemically smaller for racial and ethnic minority groups compared to Whites. However, it is still unknown whether these diminished returns also apply to marginalization based on sexual orientation. Aims: In a national sample of adults which was composed of people of color, we compared straight and homosexual people for the association between education attainment and obesity. Methods: The Social Justice Sexuality Project (SJS-2010) is a cross-sectional national survey of health and wellbeing of predominantly people of color who identify as homosexual. The current analysis included 2884 adults (age 24 or more) who were either heterosexual (n = 260) or homosexual (n = 2624). The predictor variable was education attainment, and the outcome variable was obesity status (body mass index larger than 30 kg/m 2 [kilograms per meter squared]). Demographic factors (age and gender), household income, nativity (US born vs. immigrant), and health (self-rated health and current smoking) were the covariates. Sexual orientation was the moderator. Results: In the pooled sample, high education attainment was protective against obesity status. Sexual orientation interacted with education attainment on odds of obesity, which was suggestive of stronger protective effects of high education attainment against obesity for heterosexual than homosexual individuals. Conclusion: High education attainment better protects heterosexual than homosexual people against obesity, a pattern similar to what has been observed for comparison of Whites and non-Whites. Smaller protective effects of education attainment on health behaviors of marginalized people are possibly, due to prejudice and discrimination that they experience. Discrimination may minimize stigmatized individuals’ abilities to mobilize their economic and human resources and translate them to tangible outcomes. This finding extends the Minorities’ Diminished Returns theory, suggesting that it is not just race/ethnicity but possibly any marginalizing and stigmatizing social identity that results in diminished returns of socioeconomic status resources.