The main research question that this study aims to answer is: does higher education student mobility promote the Europeanization of Portuguese universities? The number of foreigner students in Portuguese universities has grown radically since 1987, as well as the number of Portuguese students going abroad. This increase in students' mobility within the European Union (EU) is taken as a very significant indicator of the Europeanization of the Portuguese universities, i.e., the development of the European dimension of higher education. It is argue that the European dimension in education has a hybrid character: the EU provides initiatives to develop a stronger European citizenship but the Member States have to deal with the lack of resources when implementing changes and when participating in the construction of a European project. This study looks at the ERASMUS programme as tool to promote the mobility in Portuguese universities and looks for evidence that it has a significant role in the definition of the European self-identification as a step towards an efficient strategy for the development of the European dimension of higher education.