This study aimed to relate school diversity approaches to continuity and change in teacher-student relationships, comparing Belgian-majority (N=1875, M_age=14.56) and Turkish and Moroccan-minority adolescents (N=1445, M_age=15.07). Latent-Growth-Mixture-Models of student-reported teacher support and rejection over three years revealed three trajectories per group: normative-positive (high support, low rejection) and decreasing-negative (moderate support, high-decreasing rejection) for both groups, increasing-negative (moderate support, low-increasing rejection) for minority, moderate-positive (moderate support, low rejection) for majority youth. Trajectories differed between age groups. Student and teacher perceptions of equality and multiculturalism afforded, and assimilationism threatened, normative-positive trajectories for minority youth. Diversity approaches had less impact on majority trajectories. Normative-positive trajectories were related to improved school outcomes; they were less likely but more beneficial for minority than majority youth.