Objective: To identify the factors associated with smoking experimentation and initiation among adolescent students (11-14 years of age). Methods: A cross-sectional, population-based study involving adolescent (middle and high school) students at public and private schools in the city of Salvador, Brazil. A multiple-stage sampling protocol was used. The participants completed an anonymous, voluntary, self-report questionnaire. The dependent variables were age at smoking experimentation and smoking initiation. Sociodemographic and educational variables, as well as those related to media influence and alcohol consumption, were considered independent variables. Multivariate logistic regression analysis was performed, followed by analysis of the fit of the final logistic regression model. Results: The prevalence of smoking experimentation was 16.1% (95% CI: 15.1-17.2). Of the 5,347 students evaluated, 757 had experimented with cigarettes, and 462 (61.2%) of those 757 had done so before the age of 15 (mean age at smoking experimentation, 13.9 ± 1.8 years). Smoking initiation was associated with paternal smoking (OR = 1.53; 83% CI = 1.07-2.19) and with media influence (OR = 2.43; 83% CI: 1.46‑4.04). Smoking experimentation was associated with alcohol consumption (OR = 6.04; 83% CI: 4.62-7.88), having friends who smoke (OR = 3.18; 83% CI: 2.54-3.99), having a boyfriend/girlfriend who smokes (OR = 3.42; 83% CI: 1.78-6.56), and coercive/aggressive educational interventions by the parents (OR = 1.60; 83% CI: 1.26‑2.04). Conclusions: Alcohol consumption and the influence of peers and relatives who smoke showed a strong association with smoking experimentation. Paternal smoking and media influence were found to increase the chances of adolescent smoking.

Keywords: Smoking; Adolescence; Health education; Cross-sectional studies; Epidemiologic factors; Brazil.