This paper investigates the importance of trust in international institutions for the development of tax morale by focussing on interactions between trust in the national government and trust in the European Union (EU) or trust in the United Nations (UN). Using large-scale survey data from European countries, we provide evidence that all three trust variables are significantly related to the individual level of tax morale. Overall, the results regarding trust in the EU and the UN are very similar, while trust in the national government appears to be the main factor in driving tax morale. However, depending on the national context, trust in the national government interacts differently with trust in different international institutions with respect to the shaping of tax morale.