The study analyses, in both theoretical and practical aspects, the topic of hybrid warfare and threats that have become particularly relevant after Russia’s war in Ukraine. First, the authors examine the theoretical debates, concerning the definition of hybrid threats by singling out its main elements and estimating, on their basis, the definitions used by the European Union and NATO. Second, on the grounds of examples of the Baltic states and specifically of Lithuania, the article presents practical challenges related to hybrid threats and posed by Russia. Finally, the study surveys the decisions taken during recent years at the level of Lithuania, the European Union, and NATO with the exception of essential measures in fighting against hybrid threats.