As ethnic diversity rises across Europe, the Left faces a trade-off between incorporating new minorities while retaining support from settled, working-class voters. Focusing on the Labour Party’s selection of Muslims and employing a dataset containing over 42,000 local election candidates in England, this article argues that inclusion is less likely where core voters are most concerned about the representation of Muslims’ material and religious interests: economically deprived areas with sizable Muslim populations. It shows that in these areas Muslim candidates underperform at the polls and Labour Parties are less likely to choose Muslim candidates here as a result. Selection thus varies based on the economic and cultural threats that Muslim representation poses to the Left’s core constituency. These findings contribute to our understanding of the forces that shape ethnic minority political incorporation across contexts.