Abstract Background Little is known about the mechanism by which Adverse childhood experience (ACE) affects adolescent's engagement in addictive behaviours in the African context. We investigated the role of impulsivity in the link between ACE and behavioural addiction among schooled youth in Tunisia. Methods We performed a cross sectional study among 1940 schooled adolescents in the region of Mahdia (Tunisia) from January to February 2020. We used the validated Arabic version of the World Health Organization ACE questionnaire. The Barratt Impulsivity Scale as well as the Internet Addiction Test were used as screening tools for impulsivity and internet addiction. Results A total of 1940 adolescents returned the questionnaires. About 97.5% reported experiencing at least one ACE. We found that ACEs score predict addictive behaviours through impulsiveness (p < 0.001; % mediated = 16.7%). Particularly, intra-familial ACEs (p < 0.001; % mediation = 27.8%) demonstrated the most mediation by impulsivity followed by exposure to extra-familial ACEs (p < 0.001; % mediation = 10.5%). There were interactions between ACE and impulsivity in terms of their impact on internet addiction (p < 0.001; % mediation = 37.5%). Conclusions The mediation part of impulsivity in the association between ACE and cyberaddiction is alarming. Key messages Impulsive behaviors mediates the effect of childhood adversity on addictive behaviors. Great mediation part of impulsivity (37.5%) for internet addiction among Tunisian youth.