The participants were 51 percent female and 49 percent male, and had an average age of 14.07 years. They completed an anonymous self-report questionnaire during a regular class period. Self-reported aggressive and unsafe behavior were associated with initiation of drug use, including smoking tobacco, drinking alcohol, and smoking marijuana. Results revealed sex differences for aggressive behavior, victimization, and unsafe behavior. Findings have implications for prevention, because reducing drug use might also reduce aggressive and unsafe behavior. Findings suggested the desirability of expanding social skills training, which is effective in drug use prevention programs, to cover aggressive behavior and engagement in unsafe behavior. Tables and 27 references (Author abstract modified)