This study closely examines long-term outcomes of intermarriage in Denmark in terms of children's educational performance, studying grades from final examinations. The study uses rich register data, where families are linked across generations, and contributes to the migration literature by providing new insights into the human capital formation in inter-ethnic families. The outcomes of children of intermarriage are very much in line with the outcomes of children with two native-born Danish parents. Compared to second-generation immigrants, children of intermarriage perform substantially better, and these differences remain even when school and family-level confounders are taken into account. Moreover, this paper explores the heterogeneous character of the 2.5 generation in Denmark and studies the importance of parental country of origin. Parental country of origin is of significance for the educational performance of children from intermarriage in Denmark, as the performance of children with a non-native parent originating from countries of Africa, Asia, and Latin America is closer to that of second-generation immigrants, rather than natives. This association remains (for certain groups) when controlling for unobserved heterogeneity at the school and family level.