Large-scale immigration has been recently taking place in the EU and other regions of the world. At the heart of public and academic debates is the following question: are these flows of migrants a threat or an opportunity for host countries? Beyond the economic costs and benefits of immigration, the integration of immigrants into host countries’ social life constitutes an important challenge for social cohesion as well as for the wellbeing of natives and migrants. In particular, successful socio-cultural integration may lead highly skilled migrants to prolong the duration of their stay, which is beneficial to host countries. Indeed, migrants’ efforts towards socio-cultural integration and their foreseen length of stay are intrinsically related. Furthermore, the constraints and prospects set by the host country’s migration policy strongly affect the migrant’s expectations and decisions regarding integration.The first aim of this project is to analyse, both theoretically and empirically, how expectations regarding the migrant’s length of stay are formed and potentially revised in the course of the migration spell. The second objective is to study how immigration policies affect the migrants’ integration decisions. We will develop a microeconomic model to explore this question. Empirically, we will focus on highly skilled migrants and assess whether a preferential residence status positively impacts on their foreseen length of stay and on their integration. To this end, we will exploit the introduction of the European Blue Card as a natural experiment. The research questions tackled in this project are relevant to Luxembourg as more than 25% of its workforce is composed of immigrants and because Luxembourg makes an intensive use of the European Blue Card.