Although humans display inequality aversion, many people appear to be untroubled by widespread economic disparities. We suggest that such indifference is partly attributable to a belief in the fairness of the capitalist system. Here we report six studies showing that economic ideology predicts self-reported and physiological responses to inequality. In Studies 1 and 2, participants who regard the economic system as justified, compared with those who do not, report feeling less negative emotion after watching videos depicting homelessness. In Studies 3-5, economic system justifiers exhibit low levels of negative affect, as indexed by activation of the corrugator supercilii muscle, and autonomic arousal, as indexed by skin conductance, while viewing people experiencing homelessness. In Study 6, which employs experience-sampling methodology, everyday exposure to rich and poor people elicits less negative emotion among system justifiers. These results provide the strongest evidence to date that system-justifying beliefs diminish aversion to inequality in economic contexts.