The aim of this study was to assess the prevalence of cannabis use and associated factors among school-going adolescents in Algeria, Morocco, Peru, Palestine and Tonga. Using data from the Global School-Based Student Health Survey (GSHS), we assessed the prevalence of cannabis use and social correlates among adolescents (N=15226). The overall lifetime cannabis use was 3.2% and current cannabis use was 2.6%. Lifetime and current cannabis use was higher in Tonga (7.5% and 6.8%, respectively) than in any other of the five study countries. Variables positively associated with the outcome in multivariable analysis were male gender, poverty (went hungry), current smoking, having been in a physical fight, had an injury, and frequent consumption of fast food. Efforts to prevent and control cannabis use may need to address a cluster of risk behaviours, in particular cigarette smoking.