Applying a risk and protection perspective, this study paid special attention to the protective roles of parental and peer support in the face of perceived ethnic discrimination (PED) at school. Responding to the inconsistent findings of previous research, the survey study provides greater clarity regarding the interactions between PED at school, social support and positive adjustment (self-esteem, self-efficacy, optimism and school integration). The sample comprised 104 ethnic-minority youth (Mage = 17.73, SD = 3.29, 61% female), including refugee youth (n = 55) and second- and third-generation youth of immigrant descent (n = 49). Structural equation models across the whole sample confirmed peer support as a significant moderator, indicating that ethnic-minority youth who received low peer support were less optimistic when facing PED. In multi-group models, we tested whether results differ across refugee youth and youth of immigrant descent. Results revealed between-group differences concerning the moderating roles of parental and peer support: For youth of immigrant descent, while more PED was associated with lower self-esteem when receiving low parental support, we found a positive association between PED and optimism when receiving high parental support. Based on the findings that refugee youth were shown to be less optimistic when obtaining low peer support, the main interaction effect for peer support on optimism seemed to be driven by refugee youth. The results of our cross-sectional study highlight the importance of identifying specific social support factors for specific adjustment outcomes and also the importance of differentiating between minority groups. Further, the findings offer practical implications for the educational sector in terms of programs focusing on the development of peer-support networks to especially promote refugee youth resilience and resettlement in Germany.