From the pre-teen to the mid-teen years, rates of alcohol use and misuse increase rapidly. Cross-sectional research shows that positive family emotional climate (low conflict, high closeness) is protective, and there is emerging evidence that these protective mechanisms are different for girls versus boys. The aim of this study was to explore gender differences in the longitudinal impact of family emotional climate on adolescent alcohol use and exposure to peer drinking networks.Three-wave two-level (individual, within-individual over time) ordinal logistic regression with alcohol use in the past year as the dependent measure and family variables lagged by 1 year.Adolescents completed surveys during school hours.A total of 855 Australian students (modal age 10-11 years at baseline) participating in the International Youth Development Study (Victoria, Australia).These included emotional closeness to mother/father, family conflict, parent disapproval of alcohol use and peer alcohol use.For girls, the effect of emotional closeness to mothers on alcohol use was mediated by exposure to high-risk peer networks. Parent disapproval of alcohol use was protective for both genders, but this effect was larger for boys versus girls, and there was no evidence that peer use mediated this effect. Peer drinking networks showed stronger direct risk effects than family variables.Family factors unidirectionally impact on growth in adolescent alcohol use and effects vary with child gender.