This research aims to describe the process of integration of Luxembourg’s Portuguese. To achieve this, we first conduct a summary review of the sociological literature about integration. Once the conceptual framework established, we measure and link the two essential aspects of integration: the socio-economic integration and the acculturation. To complete, we confront the Portuguese population resident of Luxembourg to those residing in Portugal in order to highlight the degree of acculturation of Portuguese immigrants and their descendants with the Luxembourg society. This research has required the use of data from the Luxembourg European Values Study (EVS) of 2008 as we measure acculturation from questions about the values of individuals. We prove that compared with their parents, the descendants of Portuguese immigrants, regarding their native social environment, are experiencing upward social mobility associated with the development of an “hybrid” cultural identity, composed of values both of the country of birth of their parents and of Luxembourg.