The association of health behaviour, indicators of social adjustment, and psychosomatic symptoms with diagnosed asthma was assessed in a community-based sample of 4550 adolescents in South Western Sydney, Australia. The results of this survey found an asthma prevalence among 11-15-year-olds of 17.5%, being consistent with previous studies. Tobacco use and alcohol consumption were higher among asthmatic compared with nonasthmatic adolescents. Asthmatics reported feeling lonely more often, having a number of negative social perceptions and feelings, and having more frequent psychosomatic symptoms. The findings of the study suggest that adolescents with asthma represent an important vulnerable group of school children. Asthma education may need a greater life-style change focus, besides asthma self-management training.