This thesis is based on three papers where I examine some aspects of ethnic and gender-based prejudice and discrimination in hierarchical situations. In Paper I, the existence of ethnic hierarchies in Sweden is explored. Both immigrant and ethnic Swedes were asked to report their social distance to a number of ethnic groups represented in their geographical area. The results showed that hierarchies exist in Swedish environments and that they are connected with both ethnic prejudice and participants’ tendency to promote and support hierarchies, as expressed in their scores on social dominance orientation (SDO). In Paper II, based on Weiner’s attribution theory, ethnic and gender discrimination in social sanctions (help and punishment) were examined together with SDO in two studies. The results showed that discrimination in line with societal discrimination of subordinated groups was also displayed in the present experimental groups and that participant’s SDO is a factor behind the tendency to discriminate subordinate groups. Paper III examined sex differences in SDO in two studies. One of the strongest factors behind SDO is participant’s sex. Gender identification was tested as a mediator of the effect of sex on SDO. The results from two studies showed that the sex difference in SDO was partially or completely mediated by gender identification. The influence of SDO on formation of hierarchies and discrimination as well as its sex and gender aspects are further discussed.