Since Brexit, there has been increasing interest in democratic theory in the question of the conditions under which reversals of European integration can be considered legitimate. So far, however, the literature is very much focused on the specific case of the United Kingdom’s withdrawal from the European Union. In this article, I seek to prepare the ground for a systematic theory that clarifies, at a general level, the scope and limits as well as the actors and procedures of democratically legitimate disintegration. To that end, I map the potential democratic costs and benefits of EU disintegration. In doing so, I distinguish five types of disintegration: retreat, revocation, exit, expulsion, and dissolution. All of these measures can produce conflicts between the democratic claims of citizens and peoples. Many of these cannot be resolved but must be dealt with politically. Overall, disintegration bears more potential costs for citizens than for peoples.