Objective: To compare lung function between adolescents with and without substance use disorder (SUD)., Methods: This was an observational, cross-sectional exploratory study. The sample consisted of 16 adolescents with SUD and 24 age-matched healthy controls. The adolescents in the clinical group were recruited from a psychiatric inpatient unit for detoxification and rehabilitation; their primary diagnosis was SUD related to marijuana, cocaine, or polysubstance use. Questionnaires and pulmonary function tests were applied for clinical evaluation., Results: We found that FVC, FEV1, and their percentages of the predicted values were significantly lower in the adolescents with SUD than in those without. Those differences remained significant after adjustment for BMI and the effects of high levels of physical activity. The largest effect size (Cohen's d = 1.82) was found for FVC as a percentage of the predicted value (FVC%), which was, on average, 17.95% lower in the SUD group. In addition, the years of regular use of smoked substances (tobacco, marijuana, and crack cocaine) correlated negatively with the FVC%., Conclusions: This exploratory study is innovative in that it demonstrates the early consequences of smoked substance use for the lung health of adolescents with SUD.