In Northern Ireland, the EU Referendum debate focused on two specific issues related to the political stability of the province and the Irish border, particularly as far as the Remainers were concerned. On the one hand, it was feared that leaving the EU would threaten the peace process since it would undermine the devolution settlement, which had been signed in April 1998 (The Good Friday Agreement). On the other hand, the issue of the Irish border raised quite a bit of uncertainty in the case of Brexit. Several politicians, like Prime Minister David Cameron, insisted that border checks should be implemented since Northern Ireland, which was the only nation of the UK to have a land border with another EU member, would become a non-EU country while the Republic of Ireland would remain part of it. Would Brexit really threaten Northern Ireland’s stability? In order to answer this question and assess the role played by EU membership in this debate, this paper will first focus on the specificities of the political and constitutional context of Northern Ireland before analysing the attitude of the population and the traditional policy of the main political parties towards the EU. The concerns raised by the issues of the peace process and the Irish border during the EU referendum debate will then be examined. Finally, this article will try to assess whether these fears were justified.