The purpose of this study was to examine both the family antecedents and the outcomes of early puberty, with a particular focus on factors related to family socioeconomic status (SES). The study employed a comprehensive measurement of pubertal development and longitudinal data from the Canadian National Longitudinal Survey of Children and Youth. The sample (N = 8,440; 49% girls) included four cohorts of children who were followed biennially for 10 years, starting from age 4-11 to 14-21 years. Data were drawn at different years of age from these cohorts of children. Girls whose fathers were unemployed were more likely to experience early puberty than those whose fathers were employed. For boys, those living with fathers who had not finished secondary school were more likely to experience early puberty. Early maturing girls tended to engage in smoking and drinking at an earlier age compared with their peers. These findings provide support for psychosocial acceleration theory and suggest that different aspects of low family SES may act as a psychosocial stress for early pubertal maturation in boys versus girls, which may lead to engagement in drinking and smoking at a younger age, at least for girls.