Right-wing populists are increasingly competing for government participation, occasionally with success. Austria, Finland, Sweden, Hungary, Italy and Poland are just a few examples of European Union (EU) Member States that have seen populist parties as part of the governing coalition in recent years (Destradi et al., 2021, p. 663). While this kind of politics often seems far from military operations and their technical nature, they determine the resources and attention given to them. Populists often find other priorities than multilateral defence cooperation (Ivaldi & Zankina, 2023). This is particularly concerning at a time when European security is under threat. Less military support for Ukraine may, for example, directly affect the security situation in the rest of Europe. This Info Flash will investigate the impact of right-wing populism in EU Member States on defence and security matters, particularly on interoperability. To achieve this, I will first analyse the existing literature on defence populism. After that, these findings will be synthesised, tying them to EU security policies and the interoperability of land forces. At last, concluding remarks shall be made.