The adoption of circular economy principles can lead to the development of circular supply chains, where companies engage with other stakeholders to create circular flows. The need to collaborate with external organisations can hinder the development of circular supply chains, but the establishment of such arrangements can be facilitated by the presence of an external actor. The work by Ciulli, Kolk and Boe-Lillegraven (2020) introduces the “circularity broker”, who connects actors producing waste with other actors able to use such materials, to aid the creation of circular material flows. This study aims at exploring the facilitating role intermediaries can have in the development of circular supply chains by highlighting common functions performed and comparing them with the role of traditional supply chain intermediaries. This comparison will better define how circularity brokers can perform their facilitating role by exemplifying how traditional intermediary functions are transposed in circular settings. A further level of analysis is provided by the theoretical lens of social network theory, employed to understand how the network structure changes when circular intermediaries are introduced and highlight the most commonly recurring arrangements. A systematic literature review has been conducted to identify circular economy projects involving intermediaries, and the analysis of the retrieved papers has allowed the identification of nine common functions performed by circular intermediaries. A preliminary comparison with traditional supply chain intermediaries has shown how circularity brokers perform all the typical roles of such actors but with a stronger focus on collaboration development and facilitation, and less attention devoted to providing economic support and incentives. With respect to traditional intermediaries, various actors cover this role in circular economy settings (associations, public institutions, platforms, and single individuals).