It is well documented that attitudes toward gambling are a good predictor of problem gambling during adolescence. However, so far, little is known about what factors are associated with adolescents' gambling attitudes. This study used cross-sectional data (N = 2055, response rate 70.4%) from a representative sample of 17-year-olds in Norway to investigate the relationship between demographic, personality, motivational and social variables and gambling attitudes. Overall, adolescents' attitudes toward gambling were slightly negative. A multivariate analysis revealed that more favourable attitudes toward gambling were most strongly associated with family/peer approval of gambling. In addition, significant associations were found for gender (males more favourable); Sensation Seeking (positive association); Agreeableness (negative association); and family/peer gambling history (positive association for lifetime gambling, negative association for problematic gambling). Although a variety of individual-level and social factors are associated with more favourable attitudes toward gambling, it appears that family and peer approval of gambling are most important.