The study explored the perceived impact of a gender transformative, whole-family support intervention aimed at building adolescent girls’ protective assets against violence, among program participants in two communities of internally displaced people Maiduguri, Borno State, Northeast Nigeria. Participants reported a decreased tolerance for and perpetration of violence against girls at the household level, and endorsed their right to protection from violence at the community level. However, alongside these self-reported changes in attitude and behavior, aspects of normative, patriarchal norms governing the treatment of adolescent girls were maintained by participants. This study builds the evidence base for gender transformative, whole-family support programming and its impact on preventing violence against adolescent girls in humanitarian emergencies. Situating our findings in a feminist analysis of violence, this study calls attention to the complexity of gender norms change programming amongst families in conflict-affected settings, and highlights the need for programming which holistically addresses the relational, community, and structural drivers of violence against girls in emergencies.