Based on self-determination theory, we analyze if and how challenge-based gamification influences customers’ online shopping behavior in a way that reduces returns. We use structural equation modeling to examine our data from a survey-based online experiment with US online shoppers (n=1010). We show that our gamification approach directly affects return and purchase motivation. In addition, indirect effects are observed through a change in autonomy, competence and relatedness need satisfaction. Furthermore, we conducted regression and moderation analyses with demographic characteristics and the hexad gamification user types scale.