The growing number of EU bilateral agreements with non-member states has led to a proliferation of transversal joint institutional frameworks governing them. The importance of joint bodies with their powers to oversee, facilitate and sometimes even enforce the implementation of agreements should not be underestimated. This particularly applies in cases where joint bodies are endowed with considerable decision-making powers (for example, amendments to the agreement, binding decisions on furthering integration), as is the case with the 'association bodies' established in the 2010s under the EU's new-generation association agreements with Georgia, Moldova and Ukraine. However, to date, the roles and performance of such joint bodies have been largely neglected. This article addresses this gap in the literature by providing a comparative lawand-politics account of institutional design, legal aspects of power conferral, and functional and performative aspects of authority exercised by these association bodies.