In this paper, I study educational integration of students with migration background using data from five international student assessment studies. First, Blinder–Oaxaca decompositions are used to allow for a comparison of integration of migrant students across countries and time. In a second step, integration is related to institutional characteristics of the schooling system. Pooled, country-group and country fixed effects estimations show that time in school and early education are positively related to the integration of students with migration background. Furthermore, in the OECD countries, educational integration in science is positively related to external student assessment policies.