This study explored ethnic identity and self-esteem among 1062 Mexican-origin adolescents who were attending one of three schools, which varied in their ethnic composition (i.e., predominantly Latino, predominantly non-Latino, and balanced Latino/non-Latino). Significant relationships emerged between ethnic identity and self-esteem among adolescents in all school settings. Furthermore, controlling for generation and maternal education, adolescents attending the predominantly non-Latino school reported significantly higher levels of ethnic identity than adolescents in the other schools. Consistent with ecological theory, these findings challenge researchers to design future studies in ways such that multiple layers of context and their influence on development can be examined.