Following the Russian aggression against Ukraine in February 2022, Kyiv’s Government received unprecedented military support from NATO members. The military cooperation between Ukraine and the Atlantic Alliance goes back to the early nineties, and it underwent an intensification process after the Crimea in 2014. The Western support during the 2022 conflict took the form of economic assistance, weapons supply, and training of troops. Despite NATO’s military aid certainly played a role in Ukraine being able to resist Moscow’s aggression, problems on and off the battlefield raised concerns about the Alliance’s interoperability capacity, not only with respect to its partners but also between its Member States. Therefore, NATO Chiefs of Staff need to identify and address these issues to steer the conflict in Kyiv’s favour and to avoid the re-emergence of these issues in the future.