For immigrant youth, the development of national identity has been linked to a broad range of positive long-term outcomes, not only for these youth themselves but also for their children and grandchildren. However, the social ecosystems in which these young people live can positively or negatively impact the development of national identity—and, therefore, affect their integration into the settlement nation. Both national policy contexts and the daily interactions of students in their schools have been found to play a role in immigrants’ beliefs about and attachment to their settlement nations. In this dissertation, I explore the relationship between immigrant students’ sense of national identity, school climate, and the national policy contexts in which those schools are located, seeking to understand the degree to which school climate factors may counteract the influence of national policy contexts. Using hierarchical linear regression, I combine data on 13 European nations from the 2016 International Civic and Citizenship Education Study and from the European Union’s Migrant Integration Policy Index, analyzing the relative predictive strength and significance of a range of factors, including indices of national immigration policy, student demographics, and school factors, such as student-teacher relationships, peer relationships, and participatory engagement in the democratic processes of the school. While I find significant and positive relationships between national policy indices and immigrant students’ national identity, I find that school climate has a larger predictive strength for immigrants’ national identity than national policy contexts, pointing to the role that schools can play as countercultural sites of national incorporation in which immigrant children develop strong and positive identification with their settlement nations.