Background: during adolescence, alcohol consumption represents a new experience with the advantage of facilitating the integration of a peer group. the global overall prevalence of this risk behavior among the 15-19 years old was over 25% in 2018. however, this prevalence varies between countries. objectives: to determine the incidence and the predictors of alcohol consumption among high school students in sousse, tunisia between 2017/2018 and 2018/2019. methods: a prospective longitudinal study was conducted in four high schools in the governorate of sousse during the 2018-2019 school year. pre-trained medical doctors used an anonymous self-administered questionnaire to collect data about socio- demographic and educational features, alcohol consumption, tobacco use, illicit substances use and emotional disorders. results: participants accounted for 404. their average age was 16.4 ( 1.1) years. females represented 68%. the prevalence of alcohol consumption in 2017/2018 was 5.9% while the cumulative incidence during the 2018/2019 school year was 3.5%. among males, this incidence was of 11.9%. among females, it was of 3% (p = 0.020). illicit substance use among friends was the main predictor of becoming alcohol consumer with an adjusted odds ratio of 6.4 (95% ci: 1.9-21.3) on the other hand, having an anxiety trouble predicted less this risk behavior (adjusted odds ratio = 0.2 95% ci: 0.1-0.8). conclusions: alcohol consumption is becoming more and more common among the adolescents of sousse especially among males. the current national strategy against substances use in schools should be reinforced. implementation of a social skills training among adolescents to improve assertiveness is essential. key messages: alcohol consumption has an upword trend among the adolescents of sousse. the current prevention programs targetting adolescents in tunisia should be revised and integrate a comprehensive and multisectoral program