I study the integration of immigrants and their offspring in western societies. I take a multidimensional view on integration, disentangling three dimensions: cultural, social, and economic. This means that, rather than focusing on a single aspect of integration (e.g., do immigrants speak the host-country language?), I study integration as a much broader concept that relates to the distance between members of different ethnic groups in relation to their culture (e.g., language, religion, norms, values), their social ties (e.g., friendships, marriages, prejudice), and their resources (e.g., employment, education, health). In addition, I use a two-sided perspective on integration, meaning that not only immigrants and their offspring, but also the ethnic majority population are key actors in the integration process.