The basic idea of the paper is to investigate the differences in the ways of combating extremism between Croatia and Serbia as two neighboring countries from Southeast Europe with intertwined history and different geopolitical orientations. In order to approach this scientific interest, the notion of extremism and the ways of its suppression in liberal democracies as the basic paradigmatic determinants of this research are first theoretically elaborated. Using the thoughts and ideas of many scientists who have directly or indirectly dealt with extremism, this term is defined as a social phenomenon inherent in every man whose essence is an attack on basic human rights, and without which liberal-democratic societies lose their meaning because their basic purpose – protection of each individual member – disappears. Such notion of extremism indicates that the process of its suppression is at the same time an important and sensitive issue that needs to be dealt with moderately aiming primarily at sanctioning human actions, not thoughts. It is a democratic paradox of “tolerating the intolerant” as a sensitive attitude towards extremism in which the actions of all individuals / social groups are allowed to act until they break the law. Since this is a very complex social phenomenon, the methodological tools for determining a more successful state in the process of combating extremism are twofold. First, a comparative analysis of the legal framework examines valid constitutions, laws and strategic documents in order to compare the Croatian and Serbian attitudes towards understanding and the ways of combating extremism. Then, empirically, using the method of qualitative content analysis, the success of Croatia and Serbia in combating extremism during the period from 2000 to 2018 is compared. The data sources for the empirical research are reports from two international institutions - the NGO Human Rights Watch and the European Commission against Racism and Intolerance, as part of the Council of Europe. The results of the research indicate that Croatia is more successful than Serbia in terms of combating extremism in both the normative and empirical ways, but also that both countries have serious problems with controlling this phenomenon in their societies.