The number of bi-ethnic children is increasing. The focus of this study is on bi-ethnic students in the Netherlands with one parent with an ethnic majority background and one parent with an ethnic minority background. Most studies that have investigated educational outcomes and social functioning in school for bi-ethnic students have not focused on the diversity within this group. In this study, we described the demographic, social and cultural diversity among bi-ethnic students and examined whether, in particular, ethnic background and gender of the migrant parent were related to the educational outcomes and social functioning of bi-ethnic students. Data on a total of 653 sixth grade bi-ethnic students (age 11-12) in primary education of the national Dutch cohort study (COOL5−18) were used in this study. To analyse the relationship between the ethnic background and gender of the migrant parent and the educational outcomes and social functioning among bi-ethnic students, multivariate multilevel analyses were performed. The research findings indicate that bi-ethnic students differ demographically, socially and culturally in a manner dependent on ethnic background and gender of the migrant parent. We also found that the ethnic background and the gender of the migrant parent were related to cognitive outcomes, social-emotional functioning and citizenship competences. When trying to understand and support bi-ethnic students, we must consider the diversity among them.