Addressing specific pro-cannabis attitudes may be a viable adjunct to school-based substance abuse prevention programs. To study the predictive value of cannabis culture-related beliefs in relation to initiation of cannabis use, a prospective cohort study of 1223 students attending high school or equivalent education programs in Denmark were administered a questionnaire containing demographic information, questions about cannabis use, normative perception and personal beliefs in relation to two dimensions of cannabis culture-related beliefs: (1) beliefs about the negative consequences of cannabis use (neutralization) and (2) beliefs about positive aspects of cannabis use (glorification). Normative perception and glorification were both robustly associated with incidence of cannabis use at the 6- and 12-month follow-up. Neutralization was associated with initiated cannabis use only at the 12-month follow-up. These findings suggest that beliefs about the benefits of cannabis use may be as important in targeted programs to prevent cannabis use as beliefs about whether cannabis use is common or harmful.