Gamification (i.e., the use of game elements in non-game contexts) has been widely adopted as a persuasive design strategy in domains such as education, health, and environmental sustainability (Ahmad et al., 2021; Deterding et al., 2011; Wan Sze Cheng, 2020). In the mobility sector, findings are promising yet inconclusive, as many studies do not rigorously compare gamified interventions against non-gamified ones (Avril et al., 2024). This ongoing study addresses this gap by embedding gamification within the Stage Model of Self-Regulated Behavioral Change (SSBC) and testing it against a non-gamified SSBC condition (Bamberg, 2013). In a between-subjects experiment, participants recruited online will complete three weeks of fictional commuting decisions, choosing between bicycle, bus, or car. Both groups will receive identical onboarding and weekly performance feedback (modal share, car-use trend). Only the gamified condition will integrate game elements that structure goals and render progress salient (e.g., collecting "leaves," level advancement, symbolic rewards), while the control condition will present neutral impact cues (directional arrows) without game mechanics. Pre- and post-measures will assess perceived social norms, perceived social recognition, personal norms, goal intention, behavioral intention, perceived goal feasibility, attitude toward alternatives, and action planning. We hypothesize that gamification moderates the relationship between perceived social norms and goal intention, such that the influence of perceived norms on goal intention is stronger in the gamified condition. We also propose several hypotheses to validate the model based on the SSBC. The study advances the field by integrating gamification with a stage-based model and clarifying mechanisms in mobility change, while offering design guidance for MaaS platforms (Hensher et al., 2021). Full results and implications for research and practice will be presented at the conference.