OBJECTIVES: To assess whether adolescents with asthma experience a lower mental well-being and lower general health than their peers without asthma. STUDY DESIGN: Data from the Prevention and Incidence of Asthma and Mite Allergy study were used. At the ages of 11, 14, 17, and 20 years, 2651, 2522, 2094, and 2206 participants, respectively, completed questionnaires. Their parents completed questionnaires at the ages of 11 (n = 2660), 14 (n = 2338), and 17 years (n = 1872). Asthma was defined according to the Mechanisms of the Development of Allergy criteria. Mental well-being was measured using the Mental Health Index-5 and was reported by the adolescents. General health, measured on a 4-point Likert scale, was reported by the adolescents and their parents. We estimated associations of asthma with mental well-being and perceived general health using generalized estimating equations. RESULTS: At ages 11, 14, 17, and 20 years, 6.7%, 6.9%, 5.0%, and 6.6%, respectively, of the adolescents had asthma. Adolescents with asthma did not score differently on the Mental Health Index than their peers without asthma. Adolescents with asthma were less likely to experience good or excellent health than their peers without asthma (aOR, 0.37; 95% CI, 0.26-0.51 for intermittent asthma and 0.33; 95% CI, 0.25-0.41 for persistent asthma). These results remain similar across the different ages. CONCLUSIONS: The mental well-being of adolescents with asthma is similar to that of their peers without asthma, although adolescents with asthma are less likely to perceive a good or excellent general health.