How does supranational attachments influence attitudes on political issues such as immigration and climate change? Scholarly work on supranational identities such as European identity have predominantly focused on opinions towards the EU and EU-related policies. Yet, the literature lacks an understanding of how these supranational attachments influence opinions on other political dimensions, such as the emerging transnational cleavage. I argue that feeling attached to the EU demonstrates an attachment to a political community that transcends borders, which is then reflected in opinions on transnational issues. Using data from the European Social Survey, I show that attachment to the EU increases support for immigration, concern about climate change, and support for policies designed to combat climate change. These findings have important implications for how we understand attitudes on increasingly salient issues in European politics as well as how attachments inform those attitudes.