According to the latest official statistics, the number of immigrants in Luxembourg is approaching half the population. This demographic change raises questions concerning social inclusion, social cohesion, and intergroup conflicts. The present paper contributes to this discussion by analyzing attitudes toward immigrants and their determinants. Controlling for key socio-demographic and economic individual characteristics, we focus specifically on examining how the intensity of core contacts between nationals and inhabitants with migratory background affects attitudes toward immigrants among three groups of Luxembourg residents: natives, first-generation immigrants, and second-generation immigrants. The European Values Study data of 2008 was used in the paper. The results indicate that attitudes toward immigrants depend significantly on the origins of the residents of Luxembourg. Nationals adopt the most negative stance toward immigrants; they are followed by secondgeneration and first-generation immigrants. Attitudes of second-generation immigrants are closer to those of the native population than to those of first-generation immigrants, which confirms the assimilation hypotheses. Core contacts appear to play the most important role in the case of first-generation immigrants. The more connected the first-generation migrant to the native population, the more negative his/her opinion of immigrants.