The transition to a circular economy requires deep structural change of entire production-consumption systems. Such a systemic transition will inevitably be hampered by poor knowledge and resource transfer between various levels of society. It is therefore proposed in this chapter that a circular economy requires well-functioning ecosystems of intermediaries who can broker knowledge exchange and collaboration between different societal systems as well as geo-political scales. Sustainability intermediation has been recognised as being critical for lubricating the machinery of societal transitions, however, little is known with regards to the ecology of intermediaries required to achieve a global transition to a circular economy. In light of the challenges surrounding the effective governance of a circular economy transition, the questions this chapter seeks to explore is: how do we begin to nurture adequate ecologies of intermediaries that can facilitate the transition to a circular economy?