This article investigates the role in practice of social capital in the success and perennity of European rural development projects, taking three Walloon LEADER projects as case studies. In the context of rural areas, that carry innate characteristics – proximity, sense of community – social capital is expected to play an important role in the success or failure of development projects. Yet, in theory, social capital is mentioned by the European Commission only when referring to outputs of the approach, never as an input. By investigating three LEADER projects that were developed between 2007 and 2013 in Wallonia through qualitative analysis, from the conception of the Local Development Strategy to the current situation of projects – more than 5 years after the end of funding – we confirmed the significance of trust as a lever for development, highlighted the importance of human capital and discussed the relevance of project time-scales.