In this paper, we consider how aspirations for “who I can be” in the future could shape support for prosocial actions that benefit an ethnic out-group, relative to their own group. We suggest that aspirations are, in turn, influenced by individuals’ group memberships, which vary in their degrees of collective agency. The hypotheses were tested using data collected from Afghan youth immigrants (N = 392) and Iranian youth (N = 672), representing a relatively understudied immigrant–host context. We explored the drivers of both in-group and intergroup prosocial behaviors, and how they differed in these unique social settings. The findings indicated that in-group identification was linked to in-group but not out-group prosocial behaviors. In addition, in-group identification was associated with three components of aspirations: personal, influence, and relational. Moreover, only the relational aspiration was associated with in-group prosocial behaviors while the influence aspiration was linked to out-group prosocial behaviors. Furthermore, the study revealed that the relationships between in-group identity and all components of aspirations were fully mediated by perceived collective agency among Iranian youth, but partially among Afghan immigrants, suggesting distinct effects for disadvantaged group members. The research highlights how identities shape aspirations and behaviors for a better world.