Research and practice increasingly recognise the importance of measuring social sustainability in the agri-food sector to produce sustainable food for consumption. As a result, a diverse set of social sustainability indicators has been developed in addition to the better-studied environmental and economic dimensions. However, these social indicators are dispersed in the literature, resulting in limited structured knowledge of the social dimension of sustainability. This study provides a Systematic Literature Review of 128 research articles on assessing social sustainability in agri-food systems. By conducting an in-depth analysis of relevant social sustainability indicators in the agri-food sector, the study creates a centralised knowledge base on social sustainability indicators to guide empirical investigations in agri-food systems. Thirty-six indicators were identified and structured into eight themes. These indicators have been analysed along key dimensions for decision-making: the spatial scale, the type of agri-food system, the Theory of Change (ToC) level, and the temporal scale. Indicators were found at the farm, community/local, regional, and supra-regional spatial scales. Regarding the type of agri-food system, indicators are predominantly used for integrated and cropping systems and less for exclusive food systems analyses, livestock, forest, plantation-based systems, aquaculture, and fisheries. Activity level indicators are the most dominant considering the levels along the ToC. On temporal aspects, the keywords related to social sustainability indicators are identical before and after the SDGs but have, on average, been used much more since the advent of the SDGs in 2015. A word embedding algorithm detected shifts in the debate, with issues of water access, gender equity, and participation becoming increasingly important in assessing the social sustainability of agri-food systems. The results open up a fruitful avenue of research on integrating social sustainability indicators into decision-making processes for more sustainable food production.