Gamification is a promising approach for motivating and engaging users in nongame tasks. However, theoretical support on why and how gamification enhances users' motivation or behavior is limited. Considering the concepts of goal orientation and goal structure suggested by achievement goal theory, we prescribe gamification design as purposely creating goal structures to support users' goal adoption and achievement behaviors. This conceptual work addresses the question: what types of achievement goals can be associated with gamification design? Particularly, how can the use of gamification design help construct goal structures to support users' goal adoption? Adapting achievement goal theory, we identify three sets of achievement goals, namely, cognitive competence, social competence, and social purpose, and develop six propositions on gamification design. Each proposition is illustrated with empirical examples from the literature. This research contributes to the theoretical advancement of gamification design and provides additional insights into the motivational design of information systems.