Most monitoring and evaluation programmes for agri-environment schemes focus on understanding the environmental outcomes and the cost-effectiveness of these schemes. Evaluation of the social dimensions of agri-environment schemes, particularly the socio-cultural factors that might influence the quality of engagement with the schemes and the social wellbeing impact of scheme engagement, is limited. This is a critical gap in knowledge as there is growing recognition that without more explicit consideration of the farmers involved in land management as agents of change, the required environmental improvements will not be achieved. The aim of this paper was to undertake a systematic literature review to inform the development of a set of social indicators that can be used to measure the level of farmers’ engagement with their scheme agreement and the social sustainability outcomes from participation. Following the literature review and a short-listing ranking exercise with two sets of experts, 20 high-level (composite) social indicators and associated sub-level (component) indicators were identified. A series of scale or ranking questions that can be used to capture the indicator data were also developed and tested. This paper presents the first stage in the development of a robust set of social indicators for agri-environment schemes that will also provide a good indicator of long-term environmental outcomes.