Reflection among aid actors after the devastating genocide in Rwanda led to the realisation that humanitarian and development actors contributed to increasing tensions and exacerbating the conflict. Aid interventions have since been understood to become a part of the context – and in conflict settings, to become part of the conflict. This acknowledgement that aid is not neutral also led to the recognition that donors need to consider the inadvertent side effects of programming on conflict. Conflict sensitivity emerged as a concept and tool to help aid actors to understand the unintended consequences of aid and to act to minimise harm and achieve positive outcomes. Although conflict sensitivity originated in the humanitarian field, it has since been applied in a wide range of development, peacebuilding and statebuilding contexts. In order for conflict sensitivity to be effective and to maximise impact, it should be mainstreamed within an organisation. This requires institutional capacity, commitment and the right incentives. Conflict sensitivity also needs to be applied consistently at the different levels of intervention (project, programme, sector, policy and inter-agency); and holistically throughout the programme cycle (design and planning, implementation, and monitoring and evaluation). Monitoring and evaluation (M&E) of conflict sensitivity should be included early in the design of interventions. There must be flexibility to adapt and modify the original project design during implementation in response to M&E findings. Conflict sensitivity also needs to coincide with gender sensitivity – paying attention to the possible unintentional impacts of interventions on the lives of men and women, girls and boys.