This research tests how perceived school and peer norms predict interethnic experiences among ethnic minority and majority youth. With studies in Chile (654 nonindigenous and 244 Mapuche students, M = 11.20 and 11.31 years) and the United States (468 non-Hispanic White and 126 Latino students, M = 11.66 and 11.68 years), cross-sectional results showed that peer norms predicted greater comfort in intergroup contact, interest in cross-ethnic friendships, and higher contact quality, whereas longitudinal results showed that school norms predicted greater interest in cross-ethnic friendships over time. Distinct effects of school and peer norms were also observed for ethnic minority and majority youth in relation to perceived discrimination, suggesting differences in how they experience cross-ethnic relations within school environments.