Innovations in European Union (EU) policy making have produced a distinctive, novel mode of policy that combines components of participatory and multi-level governance for policy implementation. In this manuscript we provide a conceptualization of what we term the EU's 'mandated participatory planning' (MPP) approach. This approach is increasingly used to implement EU directives, mandating the explicit formulation of certain plans or programmes on mostly subnational or cross-national levels. Drawing on three empirical examples from (mostly) environmental policy, we argue that analysing MPP as such is useful to help identify challenges and possibilities for EU policy making. Our framework provides a means to organize inquiry and compare disparate policies, and to more broadly understand the integration of policy, planning and implementation. This perspective, in turn, sheds fresh light on familiar concepts at the intersections of multi-level governance, policy implementation and participatory governance, namely multilayer implementation, participatory implementation and polycentric governance.