The article presents the main groups of scientific explanations of jihadist terrorism, focusing on the one fundamental cause of this phenomenon. The author discusses sequentially the explanations based on: 1) religious, 2) psychological, 3) political, 4) socio-economic causes. Then he attempts to select the explanations with the greatest explanatory power. For this purpose he confronts the explanations firstly with available empirical data and then with „the fundamental problem of specificity”. The confrontation with the latter screens out the explanations that are too general and overlook the specific qualities of the jihadist terrorism.