Background : Adverse childhood experiences (ACEs) were associated with poor health outcomes and health-threatening behaviors later in life. The objective of the present study was to investigate associations between adverse childhood experiences (ACEs) and early initiation of alcohol and chat use among school going adolescents.Methods : A cross-sectional study was performed with 546 school going adolescents. The ACE International Questionnaire (ACE-IQ) was used to assess ACEs, including emotional, physical, and sexual forms of abuse and neglect, as well as household dysfunction. Alcohol and chat use was assessed by questions prepared by authors. Multiple logistic regression models were used to examine the associations between overall ACE score and alcohol use and the potential moderating effects of confounders.Results : prevalence of chat chewing behavior was 26.6% followed by alcohol use 20%, and small number of student’s use cigarette smoking and other illicit drug users (0.9%) (ganja and Shisha) each. A total of 66.2% of participants reported at least one ACE, and 5.93% reported four or more ACEs. Increased ACE scores were associated with increased risks of drinking (adjusted odds ratio [AOR] = 1.09, 95% confidence intervals [CI]: 1.00–1.09), chronic disease (AOR =1.17, 95% CI: 1.06–1.28), depression (AOR = 1.37, 95% CI: 1.27–1.48), and posttraumatic stress disorder (AOR = 1.32, 95% CI: 1.23–1.42) in adulthood. After adjusting for confounding factors, the individual ACE components had different impacts on risk behavior and health, particularly on poor mental health outcomes in adulthood.Conclusions : Alcohol and Chat use was prevalent and public health concern among school going adolescents. ACEs were significantly associated with risk behaviors, alcohol and chat use may lead poor health and educational outcomes among adolescent students and numbers of ACEs have graded association. Social support, sex, residence, parent educational status and current level of depressive symptoms were significant modulating factors, which parents, school teachers, psychologists and adolescent health care providers should give concern to decrease the effect on school going adolescents.