|The purpose of the current study is to address some of the limitations of the existing literature on adolescents with illegal sexual behavior (AISB) substance use. As the existing literature is small in scope and has been focused largely on comparisons of rates of substance use between AISB and their juvenile delinquent (JD) peers, the current study will focus on identifying potential predicates and correlates of use among AISB. The ultimate goal of the present study is to gain clarity on whether substance-using AISB more closely resemble the general juvenile delinquent population, substance-using JDs more specifically, or reflect a relatively unique subgroup. We expected substance use among AISB would be linked to several factors tied to antisocial tendencies as well as a range of variables commonly linked to increases in substance use (e.g., impulsivity). Our hypotheses were largely supported, providing further evidence that antisocial tendencies significantly influence substance use among AISB. Further, several characteristics generally tied to substance use more broadly were predictive of substance abuse scores within this population, as we expected. However, several key findings did not fit into the broader picture we anticipated of a combination of antisocial tendencies and factors typically associated with substance use, but rather appeared to better fit borderline tendencies.