In three studies we examine the link between types of national identity and support for leaving the European Union (EU). We found that national collective narcissism (but not national identification without the narcissistic component) was positively associated with a willingness to vote Leave, over and above the effect of political orientation. This pattern was observed in a representative Polish sample (Study 1, n = 635), as well as in samples of Polish youth (Study 2, n = 219), and both Polish (n = 73) and British (n = 60) professionals employed in the field of international relations (Study 3). In Studies 2 and 3 this effect was mediated by biased EU membership perceptions. The role of defensive versus secure forms of in-group identification in shaping support for EU membership is discussed.