The accessibility of attitudes and norms (i.e., how quickly they are activated from memory) has been shown to predict young adult cigarette smoking, but prior work has not examined this effect in young adolescents or with other health risk behaviors. In this study, the accessibility of attitudes and norms was used to predict young adolescent (N = 325, age M = 14.97, SD = .73) self-reported behavior and behavior intention for cigarette smoking, alcohol use, marijuana smoking, and sexual behavior. The accessibility of attitudes and the accessibility of injunctive norms were significantly related to adolescents’ health risk behavior. When controlling for current behavior, the accessibility of attitudes and of family norms were significantly related to intent to engage in these behaviors in the future. In contrast, the accessibility of peer norms was only related to reports of current behavior, not future behavior intention. This finding replicates across four behaviors when controlling for age, gender, and race, and provides strong evidence that the accessibility of relevant attitudes and social norms are important factors in young adolescent risk behavior. Implications for communication interventions to reduce teen health risk behavior are discussed.