We propose that a system of dualities at the nexus of religion and family creates outcomes that help and harm families. Using data from interviews with 198 ethnically diverse Christian, Jewish, and Muslim families, we explore a conceptual framework of ten dualities: (1) religion in family is both mundane and transcendent; (2) religion both creates and addresses relational struggles; (3) religion is a unifying and dividing force; (4) religion provides both comforts and expectations; (5) families experience both blessings and demands from God/religion; (6) families treat God as both close confidant and authority figure; (7) religiosity is both a conservative and a transformative force; (8) religions expect families to both accept certain things and reject other things; (9) religious commitments have binding and liberating features; and (10) religion both excites and calms passions. We discuss how these dualities lead to the divergent outcomes of help and harm in families.