Journal of Social and Clinical Psychology 30(1): 1-23 Although the stigma of mental illness has been widely documented, the specific processes through which psychiatric labels evoke prejudice and discrimination are not well understood. We examined how ascribing humanity to an individual labeled with mental illness may influence perceptions of dangerousness and motivations for social rejection. Study 1 revealed that a general mental illness label (compared to a general physical illness label) led to reductions in ascribed humanity, which predicted increased perceptions of dangerousness. In Study 2, participants formed impressions about an individual bearing a specific mental illness label (or a specific physical illness label) while normative behavioral information and full remission status were held constant. Under these conditions, the target labeled with mental illness evoked greater ascribed humanity. Further analyses revealed a unique effect for the target bearing the mental illness label: ascribing humanity to the target predicted reductions in perceived dangerousness, which in turn influenced social rejection. A similar mediational path was not found for the target bearing the physical illness label. We discuss the implications of ascribing humanity to people labeled mentally ill for stereotyping and stigma reduction.