Boles supported the Remain campaign in the European Union membership referendum in 2016. Boles favours a Norway-style relationship between the UK and the EU after Brexit and strongly opposes a no deal Brexit. Boles said "if at any point between now and 29 March [2019] the government were to announce that 'no deal' Brexit had become its policy, I would immediately resign the Conservative whip and vote in any way necessary to stop it from happening."