Euroscepticism has become prominent across the European Union, also in countries that were originally seen as pro-integrationist such as the Netherlands. Based on a qualitative analysis of claims in three major Dutch newspapers, I examine the mainstreaming of Euroscepticism in the Netherlands in the context of the 2009, 2014 and 2019 European Parliament elections. Mainstreaming refers to a process in which an idea becomes an integral part of debates in the public sphere. I examine the mainstreaming of Euroscepticism through a two-part analysis that centres around a fourfold typology, which distinguishes between supportive, Euroalternative, soft Eurosceptic and hard Eurosceptic claims. I find that Euroscepticism has indeed become mainstream, in debates revolving around arguments for and against the European Union. Furthermore, Euroscepticism has not just become more prominent but has also moved from an outsider to an insider perspective. Yet, it often remains unclear what Euroscepticism actually entails.