Until the 1980s, many European social democratic parties had reservations about the project of European integration. But what exactly is the status of Euroscepticism within the broader ideology of social democracy? Does honouring social democratic commitments demand rejecting European integration and membership of the EU? This article investigates this question, using debates around Europe in the social democratic parties of Great Britain, Sweden and Denmark as primary cases. Employing Freeden’s morphological approach to political ideology, the article argues that there is no necessary connection between social democracy’s core commitments and opposition to European integration. The analysis also unveils the indeterminacy of the concept of sovereignty in social democratic thought, as well as how particular national imaginaries shaped centre-left opposition to European unity.