In the past few years, gambling among adolescents has become a common health risk behavior, one that might lead to other health risk behaviors. Research on the etiology of gambling behavior among adolescents has hitherto focused primarily on the factors contributing to increased gambling severity (GS). The present study is different, in that it examines two key personality components that may help curb GS: self-control (SC) and positivity ratio (PR)--the latter being defined as the positive ratio between positive and negative affects--as factors that predict reduced GS among adolescents. A convenience sample of 595 adolescents, ages 13 to 19 (M = 15.13, SD = 1.53), from six secondary and middle schools in five major cities in Israel, was taken between February and April 2012. Four instruments were used: a Gambling Behavior Scale, the DSM-IV (adapted for juveniles), the Adolescent SC Scale, and the Positive and Negative Affect Schedule. The main findings showed that PR moderated the association between SC and GS--highlighting the importance of PR in reducing the likelihood of problem gambling and bolstering the individual's SC skills and pointing to possible preventive actions that might be taken in the community to promote healthy adolescent behavior.