This project sought to identify adolescent outcome expectancies for gambling and to evaluate their relation to gambling behavior among a sample of urban adolescents. In a preliminary study, 50 outcome expectancies were identified on the basis of a literature review or generated after surveying 35 urban high school students. These expectancies were then administered to 1,076 urban high school students. Rates of at-risk and problem gambling were 14.6% and 12.7%, respectively. Exploratory and confirmatory factor analyses were performed on randomly selected halves of the sample and identified 5 expectancy domains. In a structural equation model, material gain, negative affect, and positive self-evaluation displayed significant positive relations, and negative social consequences and parent disapproval displayed significant negative relations, to gambling behavior. The model explained 48% of the variance in gambling problems and 58% of the variance in gambling frequency. These results demonstrate the salience of gambling-related cognitions in understanding the gambling behavior among these at-risk youth and suggest that expectancies may be important prevention targets for this population.