Whereas Western European governments have devolved political authority to minority regions, governments in Eastern Europe have shied away from using decentralisation to accommodate national minorities. This article assesses how these differences affect the secessionism of minority parties. The theoretical section argues that both programmatic accommodation (i.e. when governments adopt positions in favour of decentralisation) and institutional accommodation (i.e. when governments create regions that correspond to the settlement areas of minority groups and transfer authority to the regional level) increase the likelihood that minority parties will adopt secessionist positions. Regression analyses of 83 European minority parties show that a higher level of programmatic and institutional accommodation is indeed associated with a higher likelihood of secessionism. However, increases in programmatic accommodation between 2011 and 2017 in fact decrease the likelihood that minority parties turn secessionist when using the method of first differences. Future research should therefore collect panel data on minority parties' positions. KEYWORDS Secession; decentralisation; territorial autonomy; party politics; Eastern Europe; national minorities One of the most controversial questions during the Spanish transition to democracy was the status of the Basque, Catalan and Galician minority nations. Franco had tried (and failed) to quash peripheral nationalism through centralisation and repression. The 1978 constitution embarked on the opposite path, initiating a process of decentralisation during which the Basque Country, Catalonia and Galicia swiftly adopted regional autonomy statutes and built regional institutions. Initially, this led to a moderation of both violent (Basque) and non-violent (Catalan) expressions of CONTACT Edina Sz€ ocsik