This study examined the association between a wide range of factors and young adults' gambling. Data were from the Mater-University of Queensland Study of Pregnancy. The study is based on 3691 individuals for whom data were available on self-report gambling and gambling expenditure at the 21-year follow-up. Independent variables were measured at the baseline and 14-year follow-up. Adolescents who smoked cigarettes, exhibited externalizing problems, performed poorly at high school or experienced childhood sexual abuse were more likely to gamble or spend more money on gambling at 21 years. While it is uncertain whether early interventions for those individuals who start to use substances at an early age or face difficulties due to family circumstances will impact on rates of gambling, research should examine whether intervention programmes that target modifiable factors such as adolescent school performance and externalizing behaviour reduce later gambling.