The purpose of the current study was to describe the use of a brief maltreatment assessment instrument to classify adolescents receiving alcohol or other drug (AOD) treatment services based on the extensiveness and severity of prior maltreatment. This goal is significant because maltreatment reduces the effectiveness of AOD treatment and is associated significantly with co-occurring patterns of psychiatric symptoms and sexual risk behaviors. Structured interviews were administered to 300 adolescent treatment clients (202 males, 98 females; M = 16.22 years; SD = 1.13 years) to assess childhood maltreatment experiences, past year psychiatric symptoms, and sexual risk behaviors during the past 180 days. Cluster analysis classified adolescents into unique groups via self-reported sexual abuse, physical punishment, and parental neglect/negative home environment. Significant between-cluster differences in psychiatric symptoms and sexual risk behaviors were documented using MANOVA and chi-square analyses. More severe maltreatment profiles were associated with higher scores for psychiatric symptoms and unprotected intercourse. Significant heterogeneity and distinct types within this treatment sample of adolescents supports the adaptation of selected prevention efforts to promote HIV/STI risk reduction.