Version:0.9 StartHTML:00000162 EndHTML:00001548 StartFragment:00000196 EndFragment:00001512 SourceURL:https://onlinelibrary.wiley.com/doi/10.1002/psp.70105 In the growing body of research on immigrant naturalisation, migrants from high income countries have received scant attention in their own right because of their relatively low baseline citizenship acquisition rates. Established theories predominantly explain why they would not naturalise, yet in absolute terms, many do. To better understand those exceptional cases, this article focuses specially on determinants of naturalisation of migrants from high income countries, relying on a unique probability-based survey of German emigrants augmented with country-level information from GLOBALCIT and the V-Dem project (N = 1876). In line with the notion that their original citizenship provides substantial mobility rights, including the opportunity to return to a stable, wealthy country, dual citizenship toleration is a strong predictor of their naturalisation intentions. Because the instrumental value of an additional citizenship is so low for migrants from high income countries, subjective aspects like emotional attachment to the host country and emotional detachment from the origin country matter as well. Finally, interest in host country politics and elements of participatory democracy in host countries are also associated with naturalisation intentions.