Many studies of cross-national survey data find that union members are more likely to be supportive of redistributive policies than respondents who are not union members. Analysing British, German and Swedish survey data, this article demonstrates that the union membership effect on support for redistribution varies depending on the kinds of unions to which individuals belong. Regardless of their own income, wage-earners who belong to unions whose membership encompasses a wide swath of the income distribution tend to be more supportive of redistribution than members of unions that are less inclusive. This suggests that the decline of union membership among poorly paid wage-earners—a common trend across OECD countries—has more far-reaching implications for the politics of redistribution than commonly recognised.