As part of ongoing efforts to support a diverse and robust engineering workforce and ensure that children and adults from all communities have the engineering and design thinking skills to succeed in a science, technology, engineering, and mathematics (STEM)‐rich world, identity has become a growing focus of research and education efforts. To advance our understanding of engineering‐related identity negotiation within informal STEM education contexts, we conducted an in‐depth, qualitative investigation of six adolescent girls participating in an afterschool engineering education program jointly run by two community‐based organizations and a science center. Building on the Identity‐Frame Model developed through our prior work, analysis of videotaped program sessions and secondary data from participants, program facilitators, and parents highlighted the important role that leadership‐oriented youth played in shaping the identity negotiation of participants during the programs, both in the ways they recognized and positioned the situated identities of other youth and through their influence on the activity frames that defined the nature of the engineering activities. These findings extend prior classroom studies and suggest a new lens to help teachers and program facilitators support identity negotiation for youth in STEM education programs.