In post-structurally informed research, the answer to the widely documented 'achievement gap' among ethnic minorities has been a critique of educational institutions' monocultural discourse and its exclusionary effects, thus highlighting a contingent, "discursive" conception of diversity. However, in this empirical article, 10- to 15-year-old students from two ethnically mixed schools in Denmark point to a much more concrete, social and material diversity that is laid out in terms of patterns of residence, leisure activities, and socio-economic resources at home. Over the school years, however, this social and material diversity is gradually transformed to a question of ethnicity that explains why students' opportunities for educational participation ultimately differ. From a dialectical materialist reading of Hall's concept of articulation, this article explores how this transformation is made possible in everyday school life, thus arguing that ethnic diversity is more than a contingent, discursive construction; it is closely connected to ingrained patterns of material inequity in educational practice.