Gamification has often been used to stimulate learner engagement via intangible rewards, such as virtual points and virtual badges, rather than material goods or benefits. However, not all learners value such intangible rewards; some express their desire to redeem intangible rewards for utilitarian resources or benefits. Although tangible rewards have long been considered a key gamification mechanism in commercial loyalty programs, few studies have explicitly explored its effectiveness in the context of gamified education. To address this gap, the present study used a randomized controlled trial approach to examine the effects of tangible rewards that are redeemed through intangible rewards on students' intrinsic motivation, behavioural and cognitive engagement, and learning performance in a fully online gamified flipped class. Each student was randomly assigned either to the tangible rewards group (EG = 28) or the intangible rewards group (CG = 29). The students in EG significantly outperformed those in CG in terms of intrinsic motivation, behavioural engagement, cognitive engagement and learning performance in the final exam. The results provided practical implications for instructors who plan to use tangible rewards in their gamified classes.