AIM: This paper is a report of a study to determine the demographic, personal, interpersonal and illness factors associated with asthma quality of life (QOL), as self-reported by adolescents from the United States of America (USA) and Iceland. BACKGROUND: Asthma affects 12% of children in the USA and an estimated 9% in Iceland. Limited research has addressed asthma QOL for adolescents. METHODS: This cross-sectional exploratory study included adolescents with asthma (n = 15 from the USA; n = 15 from Iceland), aged 13-17 years, primarily recruited from paediatric practices in central Kentucky, USA and Reykjavik, Iceland. Data were collected in 2006. Adolescents in the USA (47% male) had a mean age of 14.1 years (sd = 1.5); Icelandic adolescents (73% male) had a mean age of 15.1 years (sd = 1.4). Participants completed questionnaires measuring sociodemographic and asthma characteristics, degree of limitations due to asthma, self-rated health, depressive symptoms and asthma QOL. Multiple regression was used to determine predictors of asthma QOL. RESULTS: Gender was statistically significantly associated with QOL. The difference in QOL between adolescents in the USA and Iceland was not statistically significant. Statistically significant predictors of higher asthma QOL were a better rating of overall health (P