This paper examines the impact of the 2016 UK referendum and expecting Brexit on migration flows and net migration in the UK. We employ a Difference-in-Differences strategy and compare EU migration to non-EU migration before and immediately after the UK referendum of June 2016. We also investigate the potential secondary effects of the referendum on non-EU migrants by using different methodologies and various robustness checks. Our results show that after the referendum (i) migration inflows from the EU declined, (ii) emigration of EU migrants increased and (iii) net migration flows from EU countries to the UK fell. Our results are not driven by the potential spillover impacts on non-EU migrant workers. Overall, the findings show that migration in the UK declined after the Brexit referendum, even before any policy change.