This study investigates patterns in violence over 3 time points in early to midadolescence in 2 statewide representative samples of youth, one in Washington State, USA, and the other in Victoria, Australia. Comparable data collection methods in both states were used to cross-nationally compare patterns of violence, risk factors, and responses to violence (school suspensions and arrests) in 2 policy contexts. Risk factors include early use of alcohol, binge drinking, involvement with antisocial peers, family conflict, poor family management, sensation seeking, and bully victimization. These are modeled as correlates of initial violence and predictors of change in violence over a 3-year period, from ages 12–15, for participating youth. Results suggest that patterns and predictors of violence are mostly similar in the 2 states. Initial levels of violence (age 13) and change over time in violence were associated in both states with more youth school suspensions and more police arrests in Grade 9. Some cross-national differences were also shown. For example, correlations of violence with gender and violence with binge drinking were stronger in Victoria, whereas correlations of violence with early use of alcohol and with antisocial peer involvement were stronger in Washington State. Antisocial peer involvement and family conflict were significant predictors of a gradual increase in violence from Grades 7–9 for youth in Victoria only. Implications are discussed with attention to prevention and intervention efforts.