This research aims to explain and understand the organisational diversity observed in the field of Fair Trade Social Enterprises or Fair Trade Organisations (FTOs). The transversal hypothesis is that such a diversity in organisational forms may be linked to the multidimensional (economic, social and/or political) nature of Fair Trade. First, since there are virtually no typologies focused on FTOs, it is necessary to look at how organisational diversity in FT can be categorised. A typology with five categories of organisational forms is suggested. Secondly, this work explores the reasons behind organisational diversity, using both an external, explanatory perspective, and an internal, interactionist perspective. A third key issue is to explore whether FTOs experience tensions between the different dimensions of FT, and how these tensions are managed in the different types of FTOs. These issues are examined under the light of different theoretical approaches linked to “new institutionalism” (economic, sociological and entrepreneurial) and resource dependence theory. The empirical material is provided by interviews with the leaders of 57 FTOs in four European regions: Belgium, France (Rhône-Alpes), the United Kingdom (England) and Italy (Rome). Eight of these FTOs, reflecting the different categories of organisational forms, are analysed more in depth.