BACKGROUND AND OBJECTIVES No recent international studies provide evidence about its prevalence, trends, or social determinants of physical fighting in adolescents. We studied cross-national epidemiologic trends over time in the occurrence of frequent physical fighting, demographic variations in reported trends, and national wealth and income inequality as correlates. METHODS Cross-sectional surveys were administered in school settings in 2002, 2006, and 2010. Participants (N = 493874) included eligible and consenting students aged 11, 13, and 15 years in sampled schools from 30 mainly European and North American countries. Individual measures included engagement in frequent physical fighting, age, gender, participation in multiple risk behaviors, victimization by bullying, and family affluence. Contextual measures included national income inequality, absolute wealth and homicide rates. Temporal measure was survey cycle (year). RESULTS Frequent physical fighting declined over time in 19 (63%) of 30 countries (from descriptive then multiple Poisson regression analyses). Contextual measures of absolute wealth (relative risk 0.96, 95% confidence interval 0.93-0.99 per 1 SD increase in gross domestic product per capita) but not income inequality (relative risk 1.01, 95% confidence interval 0.98-1.05 per 1 SD increase) related to lower levels of engagement in fighting. Other risk factors identified were male gender, younger age (11 years), multiple risk behaviors, victimization by bullying, and national homicide rates. CONCLUSIONS Between 2002 and 2010, adolescent physical fighting declined in most countries. Specific groups of adolescents require targeted violence reduction programs. Possible determinants responsible for the observed declines are discussed.