Epidemiological studies have identified recent declines in specific types of adolescent substance use. The current study examined whether these declines varied among youth with and without a history of interpersonal victimization or posttraumatic stress disorder (PTSD). Data for this study come from two distinct samples of youth (12-17 years of age) participating in the 1995 National Survey of Adolescents (N = 3,906) and the 2005 National Survey of Adolescents-Replication (N = 3,423). Results revealed significant declines in adolescents' use of cigarettes and alcohol between 1995 and 2005; use of marijuana and hard drugs remained stable. Of importance, declines in nonexperimental cigarette use were significantly greater among youth without versus with a history of victimization and declines in alcohol use were significantly greater among youth without versus with a history of PTSD. (Contains 3 tables.)