Objective: To investigate time-trend changes in the frequency of drunkenness among European and North American adolescents. Design: Cross-sectional surveys in the 1997/1998 and 2005/2006 Health Behaviour in School-Aged Children Study (HBSC). Setting: High schools in 23 countries. Participants: A sample of 77 586 adolescents aged 15 years was analyzed by means of hierarchical linear modeling. Main Outcome Measure: The frequency of drunkenness. Results: We observed a significant increase of about 40% in the mean frequency of drunkenness in all 7 participating Eastern European countries. This increase was evident among both genders, but most consistently among girls. Meanwhile, it declined in 13 of 16 Western countries, about 25% on average. Declines in Western countries were particularly notable among boys and in North America, Scandinavia, the United Kingdom, and Ireland. Despite this gender convergence, with few exceptions (Greenland, Norway, United Kingdom) boys continued to have a higher frequency of drunkenness in 2005/2006 than girls. Conclusions: The confirmed cultural convergence implies that adoption and implementation of evidence-based measures to mitigate the frequency of adolescent drunkenness such as tax increases and restricting alcohol access and advertisement should get the same priority in Eastern European countries as in Western countries. Policy measures that might facilitate decreases in drunkenness such as server training and the promotion of alcohol-free leisure-time activities should be reinforced in Western countries. The gender convergence implies that prevention policy should be less exclusively focused on male adolescents.