This article seeks to contribute to understandings of South Korea's approach to marriage migration. Situating our analysis of marriage migration policy specifically within the recent emergence of a social investment approach to welfare, we bring together two bodies of literature that due to the methodological nationalism of much welfare state scholarship are usually treated separately. Through an examination of the policy framework governing marriage migration ‐ so‐called ‘multicultural family policies’ ‐ we find that successive Korean governments have actively sought female marriage migrants to perform various social reproductive roles as a means to secure the reproductive capacity of the nation, just as feminist scholars have argued the care work of citizen‐mothers can be understood. Our analysis also suggests that marriage migration policy in Korea constitutes a distinctly transnational dimension to its overall social investment approach, which is strongly motivated by concerns to reproduce the next generation of human capital.