This article presents a short-term longitudinal study examining bidirectional associations between academic achievement and positive peer regard among Asian American and Latinx adolescents. Specifically, our investigation distinguished between positive peer regard within and across different ethnic groups in a diverse school setting. Three hundred and thirty-five middle school students (52.8% girls; 65% Asian American, 35% Latinx; assessment at the first time point M[subscript age] = 12.27 years, SD = 0.71) were followed across two consecutive school years. Participants completed a peer-nomination inventory assessing multiple dimensions of positive peer regard (i.e., reciprocal friendship, social acceptance, and respect), and grades were obtained from school records. Academic achievement was predictive of prospective positive peer regard received from same-ethnic peers only for Asian American adolescents. In contrast, academic achievement predicted prospective positive peer regard received from cross-ethnic peers only for Latinx adolescents. These results suggest that academic achievement was linked to social gains with peers from different ethnic backgrounds for Asian American and Latinx students. The findings underscore the importance of disentangling the sources of positive peer regard in multiethnic school environments.