Abstract: | ABSTRACTIdentity fusion theory suggests that merging groups into one’s personal identity should result in heightened levels of group agency. Research on the self-expansion model complementarily indicates that including others into the self is linked to a greater feeling of self-efficacy. Across three correlational studies, we examined whether personal and group identity fusion is associated with stronger feelings of personal agency, and we propose that relatively stable feelings of clarity of self-concept would mediate this association. Individuals strongly fused with a country (Studies 1–3) and family (Study 2) exhibited greater feelings of agency and goal-adherence, and self-concept clarity emerged as a significant mediator of this association when controlling for group identification measures. |