Through two stories of youth voice, learning, and identity development in an afterschool science program for girls only, we show the ways in which such programs can be understood as important identity-building practices. We describe key dimensions of a socio-cultural approach to youth voice, learning, and identity, situated also in the context of the literature on afterschool programs. We then explore the manner in which youth voice and identity were marked by time and space. We conclude with a discussion of youth voice and ethics in collaborative research projects with youth.