Mental health disparities between sexual minority and other youth have been theorized to result in part from the effects of the stigmatization on social integration. Stochastic actor-based modeling was applied to complete network data from two high schools in the National Longitudinal Study of Adolescent Health (M[subscript age] = 15 years, N = 2,533). Same-sex attracted youth were socially marginalized in a smaller predominantly White school but not in a larger, more racially diverse school. For both schools, homophily was a critical network feature, and could represent social support for and social segregation of such youth. These findings emphasize the school context in studying the social lives of sexual minority youth and suggest that youth may be better off socially in larger and more diverse schools.