This article provides an overview of the legal status of the European Union Member States outsidethe euro area. It analyses the differences between Member States with derogation and Member States withopt-outs. The article also deals with the strict interpretation of the Maastricht convergence criteria when assessingnew applicant countries. A discrepancy was noted when comparing the so called “first-wave” MemberStates and the newcomers – Lithuania is taken as a case study Member State for this purpose. This raises thequestion of the “principle of equal treatment”. A closer look is dedicated to Sweden, having a controversialand unique position within the group of Member States with derogation. More attention is given also to theUnited Kingdom as a traditional euro-sceptic country.