Abstract The aim of this paper is to present a review of the legal, theoretical, and empirical aspects of secessions from an economic perspective. This survey provides interesting insights into recent events such as the Brexit and the threat of secession made for instance by Scotland and Catalonia. International law does not grant a general right to secede, nor does it forbid secession. Furthermore, there are several modalities of secessions, which turn out to be important for new states that want to get an international recognition. For its part, the economic theory shows that the decision for a region to remain in a country (or a union) or to secede eventually results from a trade-off between the benefits of being part of a large country,...