The social identities formed through membership on extracurricular activity groups may contribute to the frequency with which youth engage in prosocial and antisocial behavior. However, researchers have yet to disentangle the individual- and group-level processes social identification effects operate through; sex and perceived norms may also moderate such effects. Thus, we investigated the hierarchical and conditional relations between three dimensions of social identity (i.e., ingroup ties, cognitive centrality, ingroup affect) and prosocial and antisocial behavior in youth ice hockey players (N = 376; 33% female). Multilevel analyses demonstrated antisocial teammate and opponent behavior were predicted by cognitive centrality at the team level. Further, prosocial teammate behavior was predicted by cognitive centrality and ingroup ties at the individual-level. Also, perceived norms for prosocial teammate behavior moderated the relations between ingroup ties, cognitive centrality, and ingroup affect and prosocial teammate behaviour. Finally, sex moderated the relations between cognitive centrality/ingroup affect and antisocial opponent behavior. This work demonstrates the multilevel and conditional nature of how social identity dimensions relate to youth prosocial and antisocial behavior.