This article examines how religion – particularly Islam – and anti-immigrant opinion climates influence the patterns of partisanship among first-generation immigrants in Western Europe. It suggests that Muslim propensity to become partisans and identify with Christian democratic parties depends on anti-immigrant opinion climate in their host country. The analyses based on individual-level data from the European Social Survey (ESS) 2002–2019 in 19 West European democracies reveal that while Muslims are indeed less likely to become partisans in anti-immigrant host societies, the opposite is true in hospitable opinion climates. Moreover, compared to other immigrants, Muslims are less likely to identify with Christian democratic parties, but this relationship is substantively small and limited to highly anti-immigrant countries. In contrast, Muslims are more likely to align with socialist parties at all levels of anti-immigrant sentiment. These findings have important implications for debates on immigrant political integration and the future of electoral alignments in Western Europe.