The relationship of self-to-self relating and suicide has received attention in explanatory models of suicide. However, exploration of specific types of self-relationships, namely feelings of inadequacy (associated with perfectionism), self-attacking and the ability to be kind and nurturing towards the self has received limited attention in a suicidal population. The present study assessed the relative contribution of self-criticism to suicide probability, alongside established predictors of suicidal ideation; hopelessness, depression, defeat and entrapment. Participants completed measures of inadequacy, self-attacking, self-reassurance, defeat, entrapment, depression and hopelessness (N = 101). A correlation, regression and mediation analysis was undertaken. Results demonstrated that self-attacking has a direct relationship with suicide probability, alongside established predictors; entrapment and hopelessness. Depressive symptomology was not found to be a significant predictor of suicide probability in this population. Addressing particularly hostile forms of self-criticism may be a promising area in terms of future research and clinical practice. Entrapment continues to be a significant predictor of suicide risk and interventions that target this experience should be explored.