["Business Strategy and the Environment, Volume 35, Issue 5, Page 6284-6303, July 2026. ", "\nABSTRACT\nThe shift towards sustainable food production is essential to address the urgent dual challenges of climate change and population growth, with agricultural cooperatives playing a vital role in this transformation. However, many cooperatives struggle to deliver the expected value to their members. By considering cooperatives as member‐centred production systems, this research investigates relational capital's role in determining cooperative success. This study uses a sequential mixed‐methods research approach. First, we use empirical survey data from 320 farmers to test a moderated mediation model that links relational capital to collaboration activities and outcomes. Then, we use qualitative responses from 50 farmers to investigate the results obtained from the survey study further. The survey study reveals the existence of a ‘dark side’ to relational capital in agricultural cooperatives, materialised by its surprising negative moderating effect on the relationship between collaborative efforts and outcomes. The qualitative interview results reveal the underlying mechanisms that bring out this dark side, namely the effects of restriction, complaisance, and blurred lines. By revealing the existence of a dark side to relational capital and meticulously categorising the mechanisms underlying its emergence, this study extends the limited existing knowledge of the adverse effects of relational capital.\n"]