In 30 years, Luxembourg’s population grew from 500,000 in 2010 to 614,000 in 2019. This growth is largely due to immigration. The foreign population percentage reached 47,5% on 1st of January 2019 – a slight decline (-0.4%) on the previous year. This decline is in fact due to the rise in naturalizations. Since the reform of the citizenship law in 2008, Luxembourg has experienced a steady rise in naturalizations – which amounted to 684 in 2000, 4311 in 2010 and reached 11,876 in 2018. In terms of formal criteria, these new citizens belong to Luxembourg. They have to take part in parliamentary elections and can stand themselves as candidates. Yet how are these new Luxembourgish citizens perceived by the native population? Are they perceived as part of the in-group? To investigate this question, we conducted a quantitative study among 253 native Luxembourgers (65% women, Mage= 34.6, SD = 15.6) – all of whom held Luxembourgish citizenship and the majority (97%) were born in Luxembourg. We assessed the attitude towards a diverse society in general and Luxembourg in particular, adapted the allophilia scale to measure the positive attitude towards the outgroup new-Luxembourgers and assessed the perceived degree of overlap between native and new Luxembourgers. Just over half of the participants (57%) perceive a degree of overlap – which is in turn predicted by openness towards diversity and acceptance of new Luxembourgers. Implications of these findings for inclusive societies will be discussed. ; C16/SC/11337403/SWITCH/Murdock