In the wake of rapid expansion of legal gambling internationally, studies of adolescent gambling involvement and problem gambling prevalence have been carried out in numerous jurisdictions. This paper reviews adolescent gambling prevalence studies that have been carried out in North America, Europe, and Oceania. Based on this review, work is clearly needed to assess the impact of survey methods on identified prevalence rates and to improve the measurement of problem gambling among adolescents. From a substantive perspective, several clear demographic and behavioral characteristics are associated with gambling involvement and problem gambling among youth. However, early assumptions about youth gambling and problem gambling must give way to more nuanced understandings of how these phenomena change in response to changes in the social and cultural environment. We may have traveled some distance down the road toward understanding the determinants as well as the distribution of youth gambling and problem gambling, but we still have a long way to go.