AbstractFollowing the 2016 EU referendum on Britain's membership in the European Union, many people described themselves as “Leavers” or “Remainers.” Here, we examine the emotional responses associated with Brexit identities using survey data collected from two nationally representative samples of the British public in 2019 (N = 638) and 2021 (N = 2,058). Confirmatory factor analysis indicated that many in both samples had coherent Leave or Remain identities. Remain and, to a lesser extent, Leave identities (regardless of how people actually voted in the referendum) predicted distress about Brexit‐related events and clinical symptoms of depression and anxiety at both time points. Structural equation models suggested that the effect of identities on symptoms was largely mediated by distress about Brexit‐related events. We demonstrate a lasting impact of Brexit on the mental health of UK citizens and show that the formation of novel political identities has been more important in this process than voting behavior.