The aim of the article is to present the psychological roots of fundamentalism, which can be found in each type of the phenomenon, and also an attempt to show fundamentalism, as the configuration of certain personality traits. As the basis for such an interpretation of fundamentalism, serve the psychological approach, which relate to the personality, cognitive style, refer to the prejudices, as well as to the concept of authoritarian personality and its constitutive characteristics. Article raised the question of so–called “fundamentalist personality” on the basis of diversity of manifestations of this phenomenon and its correlation with the concepts of authoritarianism and dogmatism. Author also addresses psychological category of attitude, which is the starting point in the discussion of the phenomena, such as fundamentalism or nationalism. In the background of considerations is an attempt to organize knowledge on fundamentalism, taking into account the historical roots of the phenomenon, and also, as a complementary reflection, a legitimacy of identifying fundamentalism with terrorism.