BACKGROUND: The use of mobile applications ("apps") for diabetes management is a rapidly developing area and has relevance to adolescents who tend to be early technology adopters. Apps may be useful for supporting self-management or connecting young people with type 1 diabetes (T1D) with their peers. However, outside controlled trials testing the effectiveness of apps, little is known about app usage in this population. Our aim was to explore app usage among adolescents with T1D. METHODS: Diabetes MILES Youth-Australia is a national, online cross-sectional survey focused on behavioral and psychosocial aspects relevant to adolescents with T1D. Associations between app usage and demographic, clinical, and psychosocial variables were analyzed using logistic regression. RESULTS: In total, 425 adolescents with T1D responded to the app questions (mean age, 16 ± 2 years; 62% female; diabetes duration 7 ± 4 years). Overall, 21% (n = 87) indicated that they used an app for diabetes management. Of these, 89% (n = 77) reported carbohydrate counting as the most common purpose. Of those not using apps, 44% (n = 149) indicated that this was due either to no awareness of suitable apps or a belief that apps could not help. App usage was associated significantly with shorter T1D duration, higher socioeconomic status, and at least seven daily blood glucose checks. CONCLUSIONS: Only one in five respondents were using apps to support their diabetes management; most apps used were not diabetes specific. App users can be characterized as having a more recent T1D diagnosis, checking blood glucose more frequently, and being from a middle-to-high socioeconomic background.