Prejudice against individuals with mental illness stems from multiple factors, including the personality traits of those harboring the prejudiced attitudes. However, little is known about the personality processes (as opposed to static correlates) leading to negative attitudes and discrimination toward individuals with mental illness. The present research tested a mediational model in which negative attitudes against such people and resulting intentions to discriminate are distally rooted in just-world beliefs, which predispose people toward higher social dominance orientation, a well-known proximal personality predictor of general prejudice. Participants completed measures of behavioral intentions, attitudes toward individuals with mental illness, social dominance orientation, and belief in a just world. The proposed mediational model was supported, and an alternative causal model was not. These results illuminate the personality-process antecedents of attitudes toward individuals with mental illness and provide a foundation for research targeting interventions intended to reduce prejudice and discrimination against this population.