peer reviewed ; Cultural diversity due to immigration has become a key topic in many societies today. The question of how the native population experiences these developments is of prime importance for intercultural relations and sets the base for acculturation of immigrants. Drawing on attachment and multiculturalism research, we supposed here that general and specific feelings of security might be related to more positive attitudes toward cultural diversity, whereas feelings of threat might be related to less openness. More precisely, the present study investigated how natives’ general attachment (secure or fearful) as well as their specific feelings of (cultural or economic) security might be related to their expectations about acculturation of immigrants in the multicultural context of Luxembourg. The sample included N = 134 Luxembourg nationals with an average age of M = 45.02 (SD = 17.41) who filled out an online questionnaire. Results revealed that self-reported fearful general attachment was positively related to more unwelcoming acculturation orientations. Relations between general attachment and acculturation orientations were mediated by feelings of cultural security, which had strong effects on host nationals’ (un)welcoming acculturation orientations over and above general attachment. Findings suggest that (un)welcoming orientations toward immigrants, entailing openness for cultural contact and exchange, are related to feelings of cultural and economic security which are partly biased by a general secure or fearful attachment. Feelings of security seem thus to provide a secure base for tolerance and openness to cultural diversity which are needed in order to deal successfully with the challenges of today’s multicultural societies. ; IRMA