The article focuses on the North vsWilliamson debate over institutions’ efficiency. It emphasizes a paradox that stems from the fact that both authors share a common set of explanatory concepts but at the same time conclude diversely on institutions’ efficiency. This paradox can be released once is understood that despite apparent homogeneity, nie concepts such as Nirvana analysis, bounded rationality, and economic embeddedness, are used diversely by North and Williamson.