Radical right parties are not equally successful across or within all countries. Most studies have up to now relied on socio-economic, socio-structural and political factors to explain these differences. We examine whether the immigration-related political culture – consisting of integration policies and shared conservative values – in which voters are embedded influences radical right voting. We argue that more exclusive immigration-culture is related to more support for radical right parties. Furthermore, the relationship between immigration attitudes and radical right support is expected to be moderated by immigration-culture. With multilevel regression models using data from the 2011 Swiss Electoral Studies (SELECTS) we compare the effect of immigration-culture in 26 Swiss cantons. We find that cantonal immigration-culture (assessed with integration regimes and shared conservative beliefs) increases radical right support and the effect of individuals' immigration attitude on radical right support is stronger when immigration-culture is exclusive.