Background. The use of gamification to change behaviors and promote physical activity is a promising avenue to tackle the global physical inactivity pandemic and the current prevalence of chronic diseases. However, we do not have yet evidence of the effectiveness of gamified interventions with the existence of mixed results in the literature.Objective. This systematic review and meta-analysis aimed to evaluate the effectiveness of gamified interventions and their healthcare potential by testing the scalability and sustainability of their influence on physical activity (PA) and sedentary behaviors (SB).Methods. Five electronic databases (Pubmed, EMBASE, Scopus, Web of Science and CENTRAL) were searched for randomized controlled trials (RCTs) published since 2010. Eligibility criteria were based on components of PICO (participants, interventions, comparators, and outcomes). Studies were included when they used gamified interventions in daily life with an active or inactive control group, and when they assessed a PA or SB outcome. Studies were excluded when the intervention was based on an active video game using a gaming console. We conducted meta-analyses using a random effects model approach. Sensitivity analyses, influence analyses and publication bias analyses were performed to examine the robustness of our results.Results. The main meta-analysis performed on 16 studies and 2407 participants, revealed a small to medium summary effect of gamified interventions on PA behavior (g = 0.42 (95%CI [0.14, 0.69]). No statistical difference was found between different subgroups (adults vs adolescents, healthy participants vs adults with chronic diseases) and no interaction effects with moderators like age, gender or BMI, suggesting good scalability of gamified interventions. Moreover, the effect appears better on the step count (MD = +1609.56 steps per day (95%CI [372.39, 2846.73]) than on moderate-to-vigorous PA (g = 0.31 (95%CI [-0.19, 0.80]). The long-term effect (measured with follow-up averaging 14 weeks after the end of the intervention) is more volatile with a very small to small effect (g = 0.15, [0.07, 0.23]). Conclusions. This meta-analysis confirms that gamified interventions are promising to promote PA in various publics. However, if the effect persists after the end of the program, suggesting that it is not just a novelty effect due to the playful nature of gamification, it seems volatile with a small long-term effect. The integration of gamification in more global healthcare interventions could be a way to address this low sustainability. Future rigorous trials are needed to explore these perspectives.