Adolescent asthma is still a major problem with poor adherence to treatment. Globally, adolescents are devoted users of smartphone technologies and app use in asthma self-management may improve adherence. The objective of this systematic review is to assess the feasibility and efficacy of mobile technology in improving asthma outcomes in adolescents. We conducted an extensive review of the peer-review literature of studies with populations consisting of children and adolescents under 18 years in seven bibliographic databases and Google Scholar. All study designs were considered. Quality assessment of included studies were independently assessed and reported. The search identified 291 articles; of the 16 eligible full-text papers, 8 met the review criteria, reporting two interventional, two qualitative and four observational studies. Samples ranged from 12 to 21 participants. Heterogeneity related to study design and the methods of the included studies prevented meta-analysis. Nevertheless, the intervention studies reported a positive effect of smartphone apps on asthma control, medication adherence and self-efficacy. Smartphone apps may be an effective asthma control tool especially among adolescents who are major users of smartphones; however, conclusions are limited by a lack of controlled trials and adequate sample sizes.