Background: Early alcohol use is associated with an increased risk for later alcohol dependence, as well as social and mental health problems. In this study, we investigate the risk factors (internalizing and externalizing behaviors) associated with early alcohol consumption over a period of 1 year, and examine whether the association is sex-specific. Methods: U.S. inner-city adolescents (N = 1785, Mean age = 12.11) were assessed and reassessed in the sixth and seventh grades (Mean age = 13.10). Self-reported information was obtained on the lifetime level of alcohol consumption, internalizing (depression, anxiety and posttraumatic stress [PTS]), and externalizing behaviors (sensation seeking, conduct problems and affiliation with delinquent peers). Associations between the variables were examined using structural equation modeling (SEM). Results: In an adjusted SEM analysis drinking by the sixth grade was primarily associated with externalizing behaviors, whereas PTS was linked to lower levels of alcohol consumption. In addition, alcohol consumption and greater externalizing behaviors by the sixth grade predicted higher alcohol consumption by the seventh grade, whereas anxiety and African American ethnicity were associated with less alcohol consumption. No sex differences were found in the association between internalizing and externalizing behaviors and drinking. However, in the adjusted SEM analysis female sex predicted higher lifetime consumption by the seventh grade. Conclusion: Sensation seeking behavior, conduct problems and affiliation with delinquent peers should be regarded as risk factors and taken into consideration when planning prevention efforts in order to decrease alcohol use in early adolescence.