Existing evidence suggests that low socioeconomic status (SES) individuals vote for left-wing parties on economic grounds and right-wing parties on cultural grounds, while high SES individuals exhibit the opposite pattern. Although various psychological mechanisms may explain this pattern, it is still unclear whether these mechanisms mediate this relationship. In a preregistered study, we use data from 9 European countries (N = 8,750) to quantify and compare the mediating role of economic system justification, economic and symbolic threats, anti-immigrant attitudes, and national identification on the relationship between two dimensions of SES (education and subjective income) and left-right voting intentions. Anti-immigrant attitudes and immigration-specific threat best explained why low educated individuals vote for right-wing parties. In contrast, we observed a positive link between subjective income and right-wing voting, which was predominantly explained by endorsement of economic system-justifying beliefs. These findings showcase the disparity between income-related and education-related effects and highlight the heterogeneous psychological processes that underlie the relationship between SES and left-right voting intentions.