Background: Eating disorders (EDs) are often stereotyped as a “women’s health issue,” due in part to the striking gendered inequities in risk. However, this stereotype has contributed to the prioritization of gender as the dominant analytic category through which to study the epidemiology of EDs, as well as research practices that erroneously treat the observed inequities as universal, fixed, or even self-evident. There are thus important knowledge gaps regarding the social patterning and structural drivers of EDs that may be undermining equitable resource allocation and intervention. Drawing on intersectionality and other critical feminist theories, this dissertation sought to address these gaps in three specific aims: (1) to examine how gender identity intersects with gender expression, sexual orientation, and weight status to shape the social patterning of EDs; (2) to evaluate the extent to which structural sexism (i.e., systematic gender inequality in power and resources) contributes to gendered inequities in EDs; and (3) to assess whether the relationship between structural sexism and EDs differs within gender identity groups by gender expression, sexual orientation, and/or weight status. Methods: Participants came from the Growing Up Today Study (GUTS), a U.S. national cohort of ~27,000 young people that began in 1996 and is ongoing. For Aim 1, a novel multilevel modeling method for quantitative intersectionality research was used to estimate the prevalence of ED diagnoses and associated symptomology (i.e., binge-purge behaviors) for 32 intersectional strata, or subgroups defined by all possible combinations of two gender identity categories, two gender expression categories, four sexual orientation categories, and two weight status categories. For Aims 2 and 3, a composite index of U.S. state-level structural sexism was linked to the geocoded GUTS data and sequential conditional mean models were used to evaluate the overall, gender identity-specific, and intersectional stratum-specific relationships between time spent living in a structurally sexist state and subsequent risk of ED symptomology. Results: Aim 1 revealed a complex social patterning of ED prevalence characterized by meaningful levels of heterogeneity both between and within gender identity categories. Importantly, intersectional strata including multiply marginalized girls and women (i.e., those who were gender nonconforming, sexual minority, and/or living in a larger body) reported the highest prevalence of both ED diagnoses and associated symptomology. In Aim 2, it was found that each additional year of living in a state characterized by a high degree of structural sexism (e.g., large wage gaps, few legal protections) increased ED symptomology risk by up to 9%; further, girls and women who had lived in a structurally sexist state for four or more years evidenced excess risk relative to boys and men, partially explaining the observed inequities. Aim 3 integrated findings from Aims 1 and 2 by demonstrating how long-term exposure to state-level structural sexism was particularly deleterious for multiply marginalized girls and women. Conclusions: Findings from this dissertation challenge prevailing stereotypes about EDs by demonstrating their inherently intersectional and contextual nature. This work also contributes theoretical and methodological advancements for social epidemiologic research on gender and EDs, and intersectional health inequities more broadly.