The present study tests whether the magnitude of the relation between Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO) is stable across and within cultures, whether their differential relations with value orientations and sociopolitical attitudes remain stable in spite of these possible differences, and whether their differential relations point to a different genesis. For these purposes, two student samples (total N = 684), three adult samples (total N = 553), and a political activist sample (N = 69) were gathered in Belgium, and one adult sample (N = 235) was collected in Poland. Both cross- and intracultural differences in the strength of the RWA-SDO relation emerged. These can be attributed to specificities in sociopolitical context and differences in political socialization, interest, and involvement. In spite of these fluctuations, in the strength of the RWA-SDO relation, regression analyses revealed high stability of the relation between RWA-SDO and sociopolitical attitudes, and mediation analyses supported the hypothesis of their different genesis.