This study assessed self-perception as a long-term predictor of relative changes in problems related to alcohol and marijuana use in early adulthood. Self-report questionnaires were completed by a community sample of 124 individuals in the Southeastern United States who were followed longitudinally from age 19 to 27. More problems due to substance use at age 27 were predicted by participants’ negative perceptions of their social acceptance, romantic appeal, and self-worth. Predictions remained after accounting for potential confounds including gender, income, and baseline substance use problems at age 19. Social avoidance and distress in new situations at age 19 mediated the relationship between self-perception and relative changes in substance use problems, such that increases in substance use problems from age 19 to 27 were potentially explainable by the linkage of negative self-perceptions to social avoidance and distress in new situations.