With the Covid-19 pandemic apparently subsiding, mega-events are again drawing the attention of an international audience and, along with it, the interest of investors and cities as potential hosts. A mega-event may be an opportunity to attract investment and attention, but regardless of scale and desired outcomes, mega-events also have considerable environmental effects. The international research project HOMEE investigated mega-events and developed the Charter for Mega-events in Heritage-rich Cities, to support heritage preservation policies and mega-event planning in future host-cities. This paper attempts to link Circular Economy (CE) ideas and tools with the Charter for Mega-events in Heritage-rich Cities, to identify the areas of overlap and to trace potential directions of further development for the Charter. We adopt a double perspective of urban development and heritage management to understand how CE principles can be grafted onto the Charter’s key topics and enrich the sustainability component of its guidelines. The technical and environmental aspects of CE’s waste elimination, product/material reuse and nature regeneration (the ReSOLVE framework) can easily be inserted into the Charter’s guidelines on adapting the mega-event to the multiple dimensions of the host’s context, streamlining planning strategies and enhancing the role of material and immaterial heritage in mega-event planning.  At the same time, by inserting the Charter’s viewpoint into the CE agenda, we propose a further extension of CE ideas towards institutional and social fields. Through widening governance structures to involve experts and local communities in all phases of a mega-event, and by paying attention to the sensitive aspects of heritage and its criticalities, a more integrated and efficient use (and reuse) of urban resources, both as built environment but also as social and cultural configurations, can be achieved.