In the last decade, the world has witnessed increasing investments in smart city initiatives, which frequently employ data and emerging technologies to tackle complex urban challenges. Although existing literature has acknowledged the potential benefits of smart cities, such as increasing economic development and improving urban operations, their sustainability, understood as the enduring or long-term impact of specific outcomes, has been under-researched. Furthermore, the few studies touching on sustainability have focused on environmental or economic sustainability, mostly ignoring social sustainability. Therefore, this paper aims to review and synthesize the state-of-the-art research on social sustainability in smart cities. Our research questions are: (1) what are the main topics in the literature related to social sustainability in smart cities? and (2) what are the gaps that require further investigation? Our review shows that inclusion and equity are crucial components that must be considered. More specifically, civic engagement is an effective method for smart cities to better understand and respond to all residents’ social, economic, and environmental demands, enabling a more inclusive and equitable smart community.