Democracy became one of the most common political regimes that governments of many countries use. It is often being considered as peaceful as it encourages freedom and legal means of expression of discontent. Surprisingly, some democracies turn out to have more terrorist attacks than other democratic countries. If democracies encourage terrorism by their nature, then why only some of them struggle with this phenomenon? This research is concerned with the tendency of rising terrorism in some democratic countries and possible factors that determine its steadiness. The missing connection between democracy and terrorism creates an empirical puzzle that is the main question of this paper: why are some democracies more targeted by terrorists while other democratic countries do not have particular problems with it. Thereby, the main goal of this paper is to understand what factors influence the rise of terrorist incidents in some democracies (in the case of the EU countries). The main hypothesis of the paper is that there is a connection between how many migrants a democratic country is ready to accept and its vulnerability to terrorist attacks.