The literature proposes numerous supplier selection techniques; these, however, are not all equally useful in different buying situations. A description of the link between the buying situation and the most appropriate selection technique is lacking. The investigation into the buying process within an engineering, procurement and construction (EPC) environment shows how buying situations are distinctly heterogeneous and render necessary the use of varied supplier selection techniques. The proposed meta-model allows for the choice of the most appropriate supplier selection technique in relation to a specific buying situation within an EPC environment. In order to develop the meta-model, it was necessary, above all, to introduce a ranking for the various buying situations. In order to accomplish this, the contextual factors that condition the selection criteria within EPCs had to be singled out. These contextual factors were then grouped under two macro-factors: the degree of difficulty in managing the purchase and the impact of the purchase on the project. The two identified macro-factors thus allowed for the definition of a two-dimensional space in which four different buying situations were identified. For each of these, the current supplier selection techniques were analyzed, as well as the links characterizing the practice within the industry and the scope for improvement. Based on these observations and on the knowledge of existing techniques, it is now possible to determine the optimum selection technique.