This article uses as its starting point Michael Porter's model of the national ‘diamond’ to explain the role of the national environment in the competitive position of industries and firms. The authors believe, however, that the influence of national culture on the competitive advantage of nations is given too little attention in this model. In particular, strong or weak uncertainty avoidance behaviour in nations and their masculine/feminine characteristics are neglected. The national diamond rests on the base of national culture, and the latter is exogenous to the firm. In a European context, managing the different diamonds that exist itself generates competitive advantage.