To whom, through what mechanisms and for what are IOs accountable? Seeking for a substantial contribution to IR theory, the SNF project “Accountability of International Organisations” by Prof. Dr. Andonova stipulates, for the first time, that decentralised institutional structures enlarge accountability forums. Based on a comparative framework, legal instruments indeed reveal that organisations with decentralised structures are accountable to a greater variety of actors, however not necessarily through a higher number of mechanisms. These results advance the debate on accountability of IOs which has thus far generated conceptual insight and established mechanisms, however, with insufficient emphasis on the relevance of organisational structure for accountability.