The present study examined the relationship between ethnic diversity in school and educational outcomes, social-emotional functioning, and citizenship competences for bi-ethnic students. The focus of this study is bi-ethnic children with 1 non-migrant parent (with 2 non-migrant grandparents) and 1 migrant parent (with 2 foreign grandparents). It was found that the educational outcomes, social-emotional functioning, and citizenship competences of bi-ethnic students were not related to ethnic diversity. We also focused on the relationship between ethnic diversity in school and educational outcomes, social-emotional functioning, and citizenship competences for mono-ethnic students to determine whether this relationship is different for bi-ethnic and mono-ethnic students. Whereas the relationship was not significant for mono-ethnic minority students, mono-ethnic majority students' educational outcomes, social-emotional functioning, and citizenship competences were related to a school's ethnic diversity. This study indicates that the outcomes and social functioning of bi-ethnic students are not related to attending an ethnically diverse school.