Abstract Collective nostalgia is an emotion experienced when one sentimentally recalls events or things related to a particular social identity. We investigated the relationship between collective nostalgia about the United Kingdom (UK) and UK citizens' desire to leave the European Union (EU). We collected data of UK citizens twice prior to the UK's official withdrawal from the European Union ( N = 347 and N = 240) and once afterwards ( N = 236). Cross‐sectional and longitudinal analysis, utilizing cross‐lagged panel models, supported the hypothesis that collective UK nostalgia increased the desire to leave the European Union. We additionally hypothesized that the relationship between these variables would be mediated positively by ties to UK citizens and negatively by ties to EU citizens. Exploratory and longitudinal analysis, however, indicated that strength of ties to UK and EU citizens predicts levels of collective UK nostalgia which, in turn, predicts desire to leave the European Union. Specifically, ties to UK citizens were associated with increased collective nostalgia and a desire to leave the EU and ties to EU citizens were associated with reduced collective nostalgia and a desire to re‐join the European Union. We discuss the implications of the findings as well as making suggestions for future studies.