The goal of the article is to investigate the investments of Portuguese firms in Brazil from the middle of the 1990s to the early 2000s. By 2003, nearly 400 Portuguese subsidiary firms in Brazil were counted. After raising some previous empirical and theoretical topics, it is stressed the relevance of the case for the main reference models in the field of firms’ internationalization, as the Nordic School (or Uppsala Model) and the OLI paradigm of John Dunning. Moreover, the paper underlines the contribution of cultural determinants, broadly speaking, from the outset of the Portuguese-Brazilian investment process. Under this framework, the role of the common language is particularly highlighted. At the same time, a few related topics are examined, including, in some situations, the paradoxical influence of the cultural proximity on foreign investments. On the other hand, these results contribute to fulfill the theoretical gap created by the long historical neglect of the research on international factors mobility.