This study aimed to examine the role of socio-political attitudes and motivational tendencies supposed to mark closed-mindedness, as well as other relevant variables of individual differences (Disintegration, i.e., proneness to psychotic-like experiences/behaviors and Death Anxiety), in the Militant Extremist Mindset (MEM). A community sample of 600 young respondents (Serbs, Bosniaks, and Albanians, aged 18-30) was recruited within a multiethnic region of Serbia that experienced armed conflict during the break-up of the former Yugoslavia. The best-fitted SEM model, incorporating measurement and structural relationships between the variables, showed that the latent factor of Closed-mindedness predicted all three aspects of MEM as well as Neighborhood Grudge, that is, resentment toward neighboring ethnicities. The effects of Disintegration and Death Anxiety on MEM were entirely mediated by Closed-mindedness. Compared to previous findings, Closedmindedness appears to represent the most important set of cognitive and motivational tendencies that channel protracted intergroup tensions into militant extremism.