At the heart of all efforts to monitor, evaluate, measure, improve, and govern the ‘integration of migrants’ lies a fundamental—if controversial—question: who exactly are those ‘migrants’ that need integration? This chapter examines this question by analyzing three sites of integrationism: EU policy on migrant integration, integration research and Eurostat statistics on integration. A major focus in integration scholarship are not ‘migrants’ in the sense of non-citizens from abroad, but rather a specific segment of a country’s citizenry, comprised of naturalized persons and those whose parents—and sometimes grandparents—were born abroad (so-called ‘second generation’). In contrast, EU policy resisted this trend for a long time, limiting its integration framework to the formal-legal category of ‘third country nationals’ (residents who do not possess EU citizenship). However, this changed recently when the Commission’s new integration agenda broadened the scope to include also ‘EU citizens of migrant background’, bringing EU policy closer to culturalist discourses that see ‘integration’ as a problem primarily of European Muslims. The chapter illustrates how, in spite of the important sociopolitical implications of relegating certain racialized populations as unintegrated, this is often presented as a trivial and value-free technical or methodological intervention.