This study explores the longitudinal effect of adolescent volunteering behaviour on young adult volunteering and the completion of secondary school. Utilising data from the Australian sample of the International Youth Development Study, frequency of volunteering in Grade 9 (mean age = 15 years) and in young adulthood (mean age = 21 years), and completion of secondary school were measured. Mixed effect logistic regression analyses revealed that adolescent volunteering was associated with an increased likelihood of volunteering in young adulthood (Odds Ratio [OR] 1.29; 95% Confidence Interval [CI] 1.20-1.39; N= 2,648) and of Grade 12 completion (OR 1.14; CI 1.03-1.28; N= 2,648), after controlling for family socioeconomic status and adolescent school adjustment. These findings suggest that adolescent volunteering may lead to further involvement in young adult volunteering and have a positive effect on school completion.