Non-suicidal self-injury (NSSI) is considered a strong predictor of suicidal behavior, although the exact relationship between NSSI and suicide is not clear. Several factors have been suggested in previous research, including attitudes toward one’s own body, thoughts and beliefs regarding death and suicide, and the ability to cause physical harm to oneself. In the current study, the researcher obtained data from 285 young adult participants who reported a history of NSSI. Two multiple mediation models were tested in which body protection, suicide-related concerns, and acquired capability for suicide were examined as mediators of the relationship between NSSI and suicide attempt frequency. The first model, in which the predictor was NSSI frequency, was not supported. The second model, in which the predictor was NSSI versatility of methods, was partially supported; the only significant mediator was suicide-related concerns. These results add to the literature regarding the relationship between NSSI and suicide.