High rates of nonsuicidal self-injury (NSSI; 14%-17%) in adolescents and young adults suggest that some self-injurers may exhibit more or different psychiatric problems than others. In the present study, the authors utilized a latent class analysis to identify clinically distinct subgroups of self-injurers. Participants were 205 young adults with a history of 1 or more NSSI behaviors. Latent classes were identified on the basis of method (e.g., cutting vs. biting vs. burning), descriptive features (e.g., self-injuring alone or with others), and functions (i.e., social vs. automatic). The analysis yielded 4 subgroups of self-injurers, which were then compared on measures of depression, anxiety, borderline personality disorder, and suicidality. Almost 80% of participants belonged to 1 of 2 latent classes characterized by fewer or less severe NSSI behaviors and fewer clinical symptoms. A 3rd class (11% of participants) performed a variety of NSSI behaviors, endorsed both social and automatic functions, and was characterized by high anxiety. A 4th class (11% of participants) cut themselves in private, in the service of automatic functions, and was characterized by high suicidality. Clinical and research implications are discussed.