The health of people's body and mind is powerfully conditioned by social factors that affect their social identity. Consistent with this notion, there is a growing interest in the way that group memberships (and the social identities derived from belonging to these groups) affect health and well‐being. To the extent that group memberships provide individuals with meaning, support, and agency (i.e., a positive sense of social identity), health is positively impacted, constituting a “social cure”. However, when group membership is not associated with these positive psychological resources or when social identity is challenged in other ways (e.g., group membership is devalued or stigmatised), social identities may become a curse, threatening and potentially harming health and well‐being. In a range of social contexts, novel examples of these processes are brought together in the contributions to this special issue. In this editorial, we link the findings from these contributions to a set of hypotheses that emerge from the social identity approach to highlight the nuanced ways in which social identity processes are key to understanding health and well‐being (Haslam, Jetten, Cruwys, Dingle, & Haslam, forthcoming). The contributions in this special issue point to fruitful ways to develop the social cure agenda. Together they highlight the importance of social identities as powerful psychological resources that have an important role to play in managing and improving health.