Britain's unexpected vote to leave the European Union (Brexit) in June 2016 has proved divisive and damaging both within the United Kingdom and internationally. Across two correlational studies, the current research proposed a model to explain the Brexit vote, with attitudes to immigration and willingness to disagree (WD) as direct predictors of the referendum result, and internal (IMS) and external (EMS) motivation to respond without prejudice as indirect predictors. Study 1 (N = 353) and Study 2 (N = 363) both showed good fit with the model and, respectively, explained 48% and 46% of the referendum result. More positive attitudes to immigration predicted a vote to remain. Higher IMS and lower EMS predicted a vote to remain, fully mediated by attitudes to immigration. In Study 1, lower WD also predicted a vote to remain, both directly and indirectly via attitudes to immigration, although this was not replicated in Study 2. These results are discussed both in relation to the Brexit result, and the implications for motivation to respond without prejudice, WD, and political correctness more generally. Following an acrimonious campaign, the United Kingdom (UK) decided to leave the European Union (EU) in a referendum on 23 June 2016 by the narrow margin of 51.9% voting leave (Leavers) against 48.1% voting remain (Remainers) on a turnout of 72% (The Electoral Commission, 2018). This largely unexpected result (BBC News, 2016; Greenslade, 2016) has proved to be one of the most divisive events of recent British history with potentially substantial economic and political impacts not just in the United Kingdom but across the EU (Bulmer & Quaglia, 2018; Chen et al., 2018). Together with the election of Donald Trump as US President and the growth of right-wing populist parties in Europe (Greven, 2016; Lewis, Clarke, Barr, Holder, & Kommenda, 2018), the UK's vote to leave the EU (Brexit) has also been seen as part of a wider backlash across Western democracies against globalism and the postwar liberal consensus (Inglehart & Norris, 2016). Understanding the causes of Brexit, therefore, has assumed a broader significance than simply domestic politics in Britain. The Brexit result has been analysed from a number of perspectives: the demographic