The chapter examines the impact of Brexit on transnational solidarity. It explains how Brexit was triggered, in part, by concerns as to the impact of EU membership, both in terms of the UK’s identity as a member of the EU and the impact of migration. This negative impact on transnational solidarity will only continue post Brexit, particularly if the UK were to leave the EU with no deal concerning its future relationship. Some of these issues would be mitigated were the UK to leave under the terms of the current Withdrawal Agreement. Nevertheless, the chapter argues that some of the benefits of EU membership will continue post Brexit, particularly as concerns the impact of the UK’s membership of the EU on the UK constitution.