After almost 20 years since the end of the armed conflicts in former Yugoslavia, we are witnesses to the fact that the main causes of the conflicts have not been overcome. Reconciliation between ethnic groups that had been in conflict by means of economic and political cooperation, must have a psychological foundation. This study investigates the relations between Conspiracy Mentality, basic lexical social attitudes, and the factors important for Croatian-Serbian and Kosovo Albanian-Serbian reconciliation, i.e., the Ethos of Conflict and the Readiness for Reconciliation. We hypothesize that Conspiracy Mentality will predict the propensity for reconciliation over and above basic social attitudes, and that will mediate the relations between basic social attitudes and factors contributing (or preventing) reconciliation. With the samples of Serbs from Central Serbia (n = 307) and Northern Kosovo (n = 271), Conspiracy Mentality, Ethos of Conflict, Readiness for Reconciliation and five basic lexical social attitudes (Traditional Religiosity, Unmitigated Self-Interest, Communal Rationalism, Subjective Spirituality, and Inequality-Aversion) were measured. Results showed that Conspiracy Mentality is negatively related to the Readiness for Reconciliation and positively to the Ethos of Conflict. Additionally, Conspiracy Mentality predicts Ethos of Conflict over and above the basic social attitudes. Finally, Conspiracy Mentality mediates the relationships between Traditional Religiosity, Inequality-Aversion and Subjective Spirituality on the one hand, and Ethos of Conflict on the other. The results suggest that Conspiracy Mentality should be taken into consideration when creating policies and programmes focused on reconciliation.