This article presents a framework which seeks to explain social behaviour, in particular, the criminal behaviour of organised crime gangs. After having examined the existing theories and their limitations, it elaborates a new approach based on Giddens’s structuration theory. This new approach, the «interaction model», analyses society as a set of interconnecting systems within which criminal behaviour is the outcome of interaction between individual agency and structural factors. We apply it to the case of the Neapolitan camorra to show its applicability and explicative value. In particular, to explain the different camorras of the post-war period, from Pasquale ‘e Nola and Alfredo Maisto to Raffaele Cutolo’s Nuova Camorra Organizzata, Lorenzo Nuvoletta’s Nuova Famiglia, Carmine Alfieri’s Confederation, Gennaro Licciardi’s Secondigliano Alliance and the more recent De Lauro clan. It concludes by arguing that structure-agency approaches have a lot to offer.