AIM: This paper describes the design and rationale of multicenter practice-based research that aims to develop and evaluate an innovative mobile health (mHealth) intervention programme directed to promote healthy behaviours and prevent adolescent obesity. DESIGN: This study is designed as a non-randomized controlled trial with a three-arm structure. METHODS: Twelve to 16 years old participants will be recruited from schools, with access to the Internet and smartphone/tablet devices. The intervention group will be invited to engage in the TeenPower mHealth programme and divided into two subgroups: Group A (additionally engaged in a structured school-based intervention programme) and Group B (only engaged in the mHealth programme). The mHealth app includes educational resources, self-monitoring, social support, interactive training modules and motivational tools. The control group will only follow the structured school-based intervention programme. The intervention length will be 3 months, including the direct support of an interdisciplinary team (nursing, nutrition, sports, psychology, among others). This research was approved and funded in August 2017. DISCUSSION: The positive evaluation of the intervention programme will stimulate the inclusion of technologies in the promotion of salutogenic behaviours and obesity prevention. IMPACT: Adolescent obesity reached epidemic proportions. It is urgent to find effective prevention strategies to induce change at the individual, family and community level. If effective, this protocol can be used by health and exercise professionals in improving community interventions tailored to teenagers.