Background. Physical activity provides fundamental health benefits for children and youth. The aim of the study was to explore the possibility of conducting an empowerment-inspired intervention and examine the impact of the intervention in promoting moderate and vigorous physical activity (MVPA) among adolescents. Method. A nonrandomized trial with a concurrent control group was carried out. Physical activity data were collected before and after the intervention with daily questions by short message service. Self-efficacy, social support, and attitude were also measured before and after the intervention since they were possible mediators. Results. The intervention was created by the students, the researchers, and the teachers using an empowerment-based approach. Students in the intervention group (n = 21) increased their MVPA on average by 4.9 (SD = 28.9) minutes per day, and students in the control group (n = 25) reduced their MVPA on average by 25.4 (SD = 23.0) minutes per day (p = .000). Conclusions. The intervention might have contributed to a promotion of physical activity among students in the intervention group. The most valuable contribution this study provides is the knowledge that it is possible to develop and conduct an empowerment-inspired intervention to promote adolescent physical activity.