AbstractThe EU's legal system has been built on the principle of a single legal order. Undeniably, however, differentiation has crept in. The UK has been at the forefront of seeking opt‐outs and exceptions to the euro, the Schengen area and so on. After Brexit, will requests by member states for special treatment continue, or will the Brexit experience strengthen the legal order? Is the EU's legal system capable of absorbing differentiation in its fabric? This article argues that differentiation can be accommodated only so far in the Treaty arrangements without a wholescale re‐evaluation of the purpose of EU law. The UK's departure removes the member state most ready to challenge some of the fundamentals of the legal order, but the article urges caution against a full re‐characterization of the nature of EU law post‐Brexit. Instead, the article foresees a continuation of the status quo, in which differentiation exists in various forms but as exceptions to the rule, rather than the rule itself.