Lammy is a staunch advocate of British membership of the European Union. On 23 June 2018, Lammy appeared at the People's Vote march in London to mark the second anniversary of the referendum to leave the European Union. The People's Vote is a campaign group calling for a public vote on the final Brexit deal between the UK and the European Union. On 30 December 2020 he voted for the Brexit deal negotiated by Boris Johnson's Government.