Whilst the economic costs and benefits of mega-events to host cities and countries are well documented, the evaluation and nature of the social impacts of such events are less clear. Although these social impacts typically include education and skills, destination branding, social cohesion, environmental sustainability and sport development, there is currently a lack of consensus on their measurement and focus upon both benefits and costs. In an evolved mega-event landscape which must align with political, social and cultural priorities, sports governing bodies, industry partners, residents and governments are increasingly concerned with ualitative impacts. Accordingly, through a systematic review of the existing literature, this paper assesses the current state of knowledge of the social costs and benefits of mega-events, including how they are identified, defined and measured, highlighting a need for further research to fully understand the social impacts of mega-events. To our knowledge, this is the first review to examine mega-event social impact evaluation, and we therefore provide a useful evidence-based guide to mega-event stakeholders in determining cases for host bids, event planning and related legacy evaluation. Our review culminates in a research agenda, providing practical guidance for future mega-event assessment.