For more than twenty years, the United Nations Security Council, regional organizations and Member States have adopted measures to prevent resources from being made available to groups considered ‘terrorist’, or from contributing to the pursuit of terrorist purposes. This has translated into a complex web of restrictive measures, policies, and practices that a range of actors (including private actors, State agencies in charge of international assistance, and humanitarian organizations) must navigate when conducting operations where terrorist groups are present or where there is a potential risk of diversion. The legitimacy of the objective is not questioned, but the broad scope and zero-tolerance policies States adopt in the implementation of counter-terror (CT) measures increasingly restricts aid organizations’ ability to deliver impartial, life-saving assistance. This is especially the case in areas where designated terrorist groups (DTGs) are present and life-saving needs are acute – for example in Syria, Nigeria, or Yemen. Whether unintended or not, CT measures create real barriers and consequences for humanitarian action.