The negotiation and adoption of the 2013 Arms Trade Treaty (ATT) made history by including a legally binding provision connecting the proliferation and use of weapons and the prevention of gender-based violence (GBV). The implementation of this treaty could potentially move forward both the prevention of conflict and GBV, and therefore the implementation of the Women, Peace, and Security (WPS) agenda. However, recent efforts to advance this agenda continue to be stymied by political and economic interests, with global arms sales amounting to at least $80 billion. The WPS agenda and the ATT have overlapping aims and the potential to reinforce each other in promoting peace. Yet as this chapter suggests, both become meaningless at best, or counterproductive at worst, when employed to legitimize militarism and undermine peace and security. This chapter argues that the culture and political economy of militarism work against effective implementation of the ATT and WPS agenda. It suggests that successful implementation of the ATT and WPS agenda requires actors to constantly challenge the dominant norm of associating militancy with masculinity.