This study aimed to explore the possible relations between cultural attitudes, ethnic boundary markers and ethnic threat perception among Dutch native speakers. Analyses showed that the attitudes of Dutch informants towards their own language, norms and values were positive, whereas tradition and frequency of contact were less important to them. The importance of language and norms and values was also reflected in its positive relation with ethnic threat perception. Finally, the analyses showed that in addition to language, norms and values, morally supporting the host country during international events (i.e. sports or political events) is an important condition to the informants as well when considering whether an immigrant should be accepted as an integrated citizen.