Many arguments have been made for the continued good work of all-girls' schools: they prepare girls well for success in college and career, helping them be better students, better leaders, and more assertive citizens. All-girls' Catholic schools offer something more: a rationale that is rooted in the theological commitments of the Roman Catholic Church. Indeed, in a contemporary culture that routinely marginalizes adolescent girls and holds them to unattainable expectations, the Church and its theologians and religious educators - because of their commitment to human dignity and flourishing - must advance a theological anthropology that centers adolescent girls. This theological anthropology of female adolescent flourishing then provides both a rationale for the Church's continued support of all-girls' Catholic schools and a vision for the mission of these schools as they advocate for the girls they serve. All-girls' schools, therefore, can be places where the commitment to the flourishing of girls is prioritized and where the toxic milieu of contemporary culture can be resisted. In this book, Cynthia Cameron draws theological attention to female adolescence and uses the resulting robust theological anthropology to provide a theological argument for all-girls' Catholic schools. It draws from the work of developmental and clinical psychologists who work with adolescent girls, from systematic, contextual, feminist, and intersectional theologians who explore what it means for humans to be created by God in the image of God, and from educational researchers focusing on the history and mission of Catholic schools in the United States. Ultimately, it argues that, in addition to the psychosocial and educational reasons for supporting all-girls' Catholic schools, there must also be a theological reason. All-girls' Catholic schools must be committed to the dignity and goodness of girls, to the basic truth that girls are already good as they are and not just for the adults that they may become.