The duty to respect international humanitarian law (IHL) in military operations requires effective tools of compliance. Peace operation forces are seldom involved in armed conflict and IHL applies formally only in a minorityof operations. The increasingly volatile environments in which peace operation personnel are required to work, and the trend of enforcement capabilities of such forces, will arguably make the question of compliance with IHL all the more important. Multinational peace operations often include a range of actors–such as the UN, another organisation leading the operation, troop contributing nations (TCNs) and the host state. Differences in training and education as well implementation of IHL in different TCNs makes compliance with IHL in multinational operations a challenging task. The use of special units with their culture of secrecy involves other complex questions. On a more general level, it is not clearly established how responsibility under international is dividedamong the main actors in a multinational peace operation. A number of practical measures are suggested to overcome challenges to an effective compliance of IHL.