The 2013 Arms Trade Treaty (ATT) offers the first comprehensive, global and legally binding standards on the trade and transfer of conventional arms. The idea for the treaty was conceived not in the boardrooms of weapons manufacturers, nor in the assembly halls of statecraft, but rather by civil society activists and Nobel Laureates – practitioners, academics, survivors and researchers and advocates. And its robust provisions on human rights, humanitarian law and gender were championed by states often marginalized by traditional arms control. The resultant treaty is a sort of ‘platypus’ of international law – simultaneously an arms control regime, an instrument of human rights and humanitarian law and a trade agreement. Given its widespread acceptance and likely rapid entry into force, it could have a wide-ranging impact on global policy making in many issue areas. But as with any new framework of global policy, the ATT represents a compromise, recognizing the legitimacy of states' rights to trade in weapons. This special section on the ATT, written from the perspective of scholars and practitioners associated with the civil society campaign that championed the treaty, reviews the ATT's normative implications, role of NGOs and implementation challenges.