The Australian Temperament Project (ATP) is an ongoing, longitudinal study following young people’s psychosocial development from infancy to adulthood, investigating the contribution of personal, family, peer and broader environmental factors to adjustment and wellbeing. Commencing in 1983, this internationally renowned study has so far collected 15 waves of data across the first 28 years of life. The ATP is investigating the development of problems such as learning difficulties, antisocial behaviour, substance abuse, anxiety and depression, as well as positive development including social competence, supportive family and peer relationships and civic participation.