This article proposes a gamification approach that aims to motivate students in online discussions. While some efforts have been made in gamification for teaching and learning, insufficient attention has been paid to gamification grounded in "both" theories and evidence from empirical studies. After identifying five motivational needs of students from the literature on online discussions, this article offers five design guidelines to address these five needs by taking a gamification approach. Each guideline consists of several implementations of how to effectively use common game elements to address each of the needs. The implementations were constructed based on theories pulled from the literature on games and prior studies on gamification in teaching and learning. Implications for research and development are discussed.