People with mental illness can internalize public prejudice and negative emotional reactions to their group, leading to self-contempt. This study examined self-contempt related to having a mental illness as predictor of suicidality among 77 people with mental illness in Southern Germany. Self-contempt, depressive symptoms, hopelessness, and suicidality were assessed at baseline; suicidality was measured again 3 months later. High self-contempt at baseline predicted increased suicidality at follow-up, adjusting for baseline suicidality, symptoms, diagnosis, age, sex, and hopelessness. These results suggest that self-contempt may be a risk factor for suicidality and call for specific interventions targeting self-stigma and its emotional consequences.