The present study is concerned with cultural diversity climate at school and how it relates to acculturation orientations and psychological school adjustment of early adolescent immigrants. Specifically, the distinct role of two types of diversity policy is investigated, namely (a) fostering equality and inclusion and (b) acknowledging cultural pluralism. Longitudinal multilevel analyses based on 386 early adolescent immigrant students (Mage = 10.49 years) in 44 ethnically heterogeneous classrooms in Germany revealed that the manifestations of both types of policies promote psychological school adjustment (i.e., better well‐being and fewer psychological and behavioral problems) at the individual level. However, they differ in their effects on acculturation orientations. At the classroom level, equality and inclusion promote assimilation. Implications for research and educational practice are discussed.