Young people are growing up in increasingly “super-diverse” societies, and show variations in how they approach diversity and embrace differences. Developing a good understanding of why some youth appreciate and value diversity whereas others do not is crucial in identifying ways to promote social interactions among different groups in broader society. The current study examined whether adolescents follow different trajectories in their views on diversity, and identified possible factors behind how they change over time. The sample included 1362 adolescents residing in Sweden (Mage = 13.18, SD = 0.43, 48% girls). Adolescents reported on their openness to diversity and classroom social climate. The peer nominations method was used to measure majority-minority friendship, and friends’ views on diversity. Latent growth analysis showed that adolescents, on average, became more open to diversity over time, but with clear heterogeneity. Three distinct trajectories were identified as: high-increasing, average-increasing, and average-declining. Relative to the high-increasing group, the other two were more likely to be male and immigrant. Relative to the high-increasing group, adolescents on the average-increasing trajectory perceived their classroom climate as less cooperative, while the adolescents on the average-declining trajectory were less likely to have friends with positive views on diversity. The findings suggest that schools may serve as a shared ground for promoting openness to diversity.