The success of industrial districts in Europe has attracted the interest of development economists in their search for new industrial development models. This study explores the extent to which the industrial district 'model' explains the realities of four footwear clusters in Italy, the 'land' of districts, and in Mexico, a less developed country. Empirical investigation confirms that there are gains from clustering; however, differences have also been identified in the intensity and quality of collective effects between the realities studied and the 'model'. Those differences are attributed to disparities in the external environments, to heterogeneity of economic actors, and to the adoption of a dynamic approach to interpret cluster growth trajectories.