In light of increased pressure on multilateral institutions, this article assesses the contribution of international organizations (IOs) to shaping international law. For that purpose, it analyses the recent work of the International Law Commission (ILC) regarding the role of IOs and its reception by States. The article argues that States do not perceive IOs as a relic of bygone times. Instead, the sceptical attitude of some States seems to be based primarily on a lack of conceptual clarity with regard to IO practice. Yet, a changing geopolitical landscape increases the pressure on lawyers to explain firstly, that the relevance of IO practice finds support in international law (and not only in favourable power relations), and secondly, that the law provides means to integrate a more plural international order within a common framework. On that basis, the article sketches possible approaches to four issues which were left open by the ILC.