Recently, increasing attention has been paid to intermediaries, actors connecting multiple other actors, in transition processes. Research has highlighted that intermediary actors (e.g. innovation funders, energy agencies, NGOs, membership organisations, or internet discussion forums) operate in many levels to advance transitions. We argue that intermediation, and the need for it, varies during the course of transition. Yet, little explicit insight exists on intermediation in different transition phases. We integrate existing conceptual models on transition dynamics and phases and a typology of transition intermediaries to examine how intermediaries advance transitions in different phases. We illustrate our conceptual insights through examp...