Using a novel dataset from Ant Forest, a mini-app within Alibaba’s flagship fintech platform Alipay, we examine how gamified social interactions influence users’ green investment decisions. We find that the users’ green preference, measured by daily low-carbon activities, is enhanced when they engage more in gamified social interactions designed for environmental education, thereby increasing their investment proportion in green mutual funds. We also provide suggestive, but only suggestive, evidence that green education may play a role in shaping users’ green preferences through gamification. Our findings are stronger among male and younger users and those less involved in environmental conservation actions. Our study provides the first mechanism in which gamified social interactions facilitate green investments by enhancing individuals’ green preferences.