Retirement villages are a model of extra-care housing, offering purpose-designed housing that incorporates both care services and a range of non-care-related facilities and activities. These generate opportunities for formal and informal social activity, and promote community engagement, solidarity between residents, and active and independent ageing. Providers suggest that retirement villages are able to foster an environment rich in social capital. This study's purpose is to review and summarise key findings on the topic of social capital in retirement villages in the gerontological literature. Social capital is defined as both an individual attribute of single actors and a feature of communities as a whole. A clear conceptualisation of social capital is used to organise the reviewed studies along different dimensions: on an individual level, social networks, trustworthiness and obligations are differentiated, while the collective level distinguishes between system control, system trust and system morality. Thirty-four studies are reviewed. While retirement villages are generally described as friendly places with widespread helping behaviour where new friends are made, research has also highlighted the difficulty of socially integrating the frail and very old. While, in particular, social networks and system morality have received much attention, there is a clear need for future research into the other domains of social capital.