There is a paucity of research examining prospective predictors of problem gambling. The current study utilised a large longitudinal data set (N = 2328) to examine a large range of adolescent risk and protective factors for problem gambling in young adulthood. These risk and protective factors covered the domains of the community, family, school, peer group and individual. Numerous predictors associated with the family, school and peer-individual were statistically significant in analyses adjusted for gender and age. However, in the fully adjusted multivariate analyses, only two predictors were statistically significant. Within this model, gender (female) was associated with a reduced risk of young adult problem gambling, while family rewards for prosocial involvement moderated the risk relationship between adolescent alcohol use and young adult problem gambling. These findings highlight the importance of adolescent alcohol use and family environment as potentially modifiable predictors of young adult problem gambling.