A sizable body of literature reports that social capital, derived from relational resources embedded in micro social contexts, is crucial for student achievement. This study aimed to examine whether this applies as well to socioeconomically disadvantaged immigrant adolescents in the US. In so doing, the study first identified the types of relational features that were strongly associated with immigrant adolescents’ academic achievement, before exploring how high- and low-achieving immigrant adolescents coming from similarly socioeconomically disadvantaged backgrounds differed in terms of these relational features. To this end, the study used the dataset of the Children of Immigrants Longitudinal Study (CILS). There was a significantly positive association found between academic achievement and a number of positive characteristics of social relationships with friends and teachers. In addition, a significant disparity in these relational features was found between high and low achievers among the socioeconomically disadvantaged. The findings illuminate the salience of peer contexts and of interpersonal trust in shaping immigrant adolescents’ educational outcomes in a way that transcends socioeconomic boundaries. It is pertinent for educators and policy-makers to empower immigrant youth as independent agents capable of generating academically relevant social capital on their own outside their families and ethnic communities.